Exhibit 5.1

Our ref       SQG/851499-000001/32993670v1

JIADE LIMITED

18/F, Block D, Huirong Plaza,

No. 88, Section 3, Jinhua Road Jinjiang District,

Chengdu City, Sichuan Province

The People’s Republic of China, 610000

14 August 2025

Dear Sirs

JIADE LIMITED

We have acted as Cayman Islands legal advisers to JIADE LIMITED (the “Company”) in connection with the Company’s registration statement on Form F-1, including all amendments or supplements thereto, filed with the United States Securities and Exchange Commission (the “Commission”) under the United States Securities Act of 1933, as amended (the “Act”) (including its exhibits, the “Registration Statement”) relating to the offering by the Company of up to 20,000,000 Class A ordinary shares of par value US$0.0001 each of the Company (the “Class A Ordinary Shares”).

We are furnishing this opinion as Exhibits 5.1 and 23.3 to the Registration Statement.

Documents Reviewed

For the purposes of this opinion, we have reviewed only originals, copies or final drafts of the following documents:

1.1

The certificate of incorporation of the Company dated 20 February 2023 issued by the Registrar of Companies in the Cayman Islands.

1.2

The second amended and restated memorandum and articles of association of the Company as adopted by a special resolution passed on 23 May 2025 (the “Memorandum and Articles”).

1.3

The written resolutions of the board of directors of the Company dated 14 August 2025 (the “Board Resolutions”).

1.4

A certificate of good standing dated 13 August 2025 issued by the Registrar of Companies in the Cayman Islands (the “Certificate of Good Standing”).

1.5

A certificate from a director of the Company, a copy of which is attached hereto (the “Director’s Certificate”).

1.6

The form of securities purchase agreement to be entered into between the Company and the purchasers named therein.

1.7

The Registration Statement.

Assumptions

The following opinions are given only as to, and based on, circumstances and matters of fact existing and known to us on the date of this opinion letter. These opinions only relate to the laws of the Cayman Islands which are in force on the date of this opinion letter. In giving these opinions we have relied (without further verification) upon the completeness and accuracy, as of the date of this opinion letter, of the Director’s Certificate and the Certificate of Good Standing. We have also relied upon the following assumptions, which we have not independently verified:

2.1

Copies of documents, conformed copies or drafts of documents provided to us are true and complete copies of, or in the final forms of, the originals.

2.2

All signatures, initials and seals are genuine.

2.3

The Company will have sufficient authorised but unissued Class A Ordinary Shares in its authorised share capital to effect the issue of the Class A Ordinary Shares at the time of issuance.

2.4

There is nothing contained in the minute book or corporate records of the Company (which, other than the records set out in paragraphs 1.1 to 1.4 of this opinion letter, we have not inspected) which would or might affect the opinions set out below.

2.5

There is nothing under any law (other than the laws of the Cayman Islands) which would or might affect the opinions set out below.

2.6

The Company will receive money or money’s worth in consideration for the issue of the Class A Ordinary Shares and none of the Class A Ordinary Shares were or will be issued for less than par value.

Opinion

Based upon the foregoing and subject to the qualifications set out below and having regard to such legal considerations as we deem relevant, we are of the opinion that:

3.1

The Company has been duly incorporated as an exempted company with limited liability and is validly existing and in good standing with the Registrar of Companies under the laws of the Cayman Islands.

3.2

The authorised share capital of the Company is US$50,000 divided into 500,000,000 shares of a par value of US$0.0001 each consisting of (a) 395,000,000 Class A ordinary shares of a par value of US$0.0001 each (b) 75,000,000 Class B ordinary shares of a par value of US$0.0001 each and (c) 30,000,000 preference shares of a par value of US$0.0001 each.

3.3

The issue and allotment of the Class A Ordinary Shares have been duly authorised and when allotted, issued and paid for as contemplated in the Registration Statement, the Class A Ordinary Shares will be legally issued and allotted and (assuming the purchase price therefor has been paid in full) fully paid and non-assessable. As a matter of Cayman Islands law, a share is only issued when it has been entered in the register of members (shareholders).

3.4

The statements under the caption “Taxation” in or incorporated by reference into the prospectus forming part of the Registration Statement, to the extent that they constitute statements of Cayman Islands law, are accurate in all material respects and that such statements constitute our opinion.

Qualifications

The opinions expressed above are subject to the following qualifications:

4.1

To maintain the Company in good standing with the Registrar of Companies under the laws of the Cayman Islands, annual filing fees must be paid and returns made to the Registrar of Companies within the time frame prescribed by law.

4.2

Under the Companies Act (As Revised) (the “Companies Act”), the register of members of a Cayman Islands company is by statute regarded as prima facie evidence of any matters which the Companies Act directs or authorises to be inserted therein. A third party interest in the shares in question would not appear. An entry in the register of members may yield to a court order for rectification (for example, in the event of fraud or manifest error).

4.3

The obligations of the Company may be subject to restrictions pursuant to:

(a)

United Nations and United Kingdom sanctions extended to the Cayman Islands by Orders in Council; and

(b)

sanctions imposed by Cayman Islands authorities under Cayman Islands legislation.

4.4

In this opinion the phrase “non-assessable” means, with respect to the shares in the Company, that a shareholder shall not, solely by virtue of its status as a shareholder, and in absence of a contractual arrangement, or an obligation pursuant to the memorandum and articles of association, to the contrary, be liable for additional assessments or calls on the shares by the Company or its creditors (except in exceptional circumstances, such as involving fraud, the establishment of an agency relationship or an illegal or improper purpose or other circumstances in which a court may be prepared to pierce or lift the corporate veil).

Except as specifically stated herein, we make no comment with respect to any representations and warranties which may be made by or with respect to the Company in any of the documents or instruments cited in this opinion or otherwise with respect to the commercial terms of the transactions, which are the subject of this opinion.

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement and to the reference to our name under the headings “Enforceability of Civil Liabilities” and “Legal Matters” and elsewhere in the prospectus included in the Registration Statement. In giving such consent, we do not thereby admit that we fall within the category of the person whose consent is required under Section 7 of the Act, or under the Securities Exchange Act of 1934, in each case, as amended, or the regulations promulgated thereunder.

Yours faithfully

/s/ Maples and Calder (Hong Kong) LLP

Maples and Calder (Hong Kong) LLP

Annexure

Director’s Certificate

August 14 2025

To:

Maples and Calder (Hong Kong) LLP

26th Floor, Central Plaza

18 Harbour Road

Wanchai, Hong Kong

Dear Sirs

JIADE LIMITED (the “Company”)

I, the undersigned, being a director of the Company, am aware that you are being asked to provide a legal opinion (the “Opinion”) in relation to certain aspects of Cayman Islands law. Capitalised terms used in this certificate have the meaning given to them in the Opinion. I hereby certify that:

The Memorandum and Articles remain in full force and effect and are unamended.

The Board Resolutions were duly passed in the manner prescribed in the Memorandum and Articles (including, without limitation, with respect to the disclosure of interests (if any) by directors of the Company) and have not been amended, varied or revoked in any respect.

The shareholders of the Company have not restricted or limited the powers of the directors in any way and there is no contractual or other prohibition (other than as arising under Cayman Islands law) binding on the Company prohibiting it from issuing and allotting the Class A Ordinary Shares.

The directors of the Company at the date of the Board Resolutions and as at the date of this certificate were and are as follows:

Yuan Li

Shaoping Lu

Shuang Qiu

Xiaohui Li

Shang Wu

Each director of the Company considers the transactions contemplated by the Registration Statement to be of commercial benefit to the Company and has acted bona fide in the best interests of the Company, and for a proper purpose of the Company in relation to the transactions which are the subject of the Opinion.

To the best of my knowledge and belief, having made due inquiry, the Company is not the subject of legal, arbitral, administrative or other proceedings in any jurisdiction and neither the directors nor Shareholders have taken any steps to have the Company struck off or placed in liquidation. Further, no steps have been taken to wind up the Company or to appoint restructuring officers or interim restructuring officers, and no step has been taken to appoint a receiver in relation to any of the Company’s property or assets.

No interest in the Company constituting shares, voting rights or ultimate effective control over management in the Company is currently subject to a restrictions notice issued under the Beneficial Ownership Transparency Act (As Revised).

I confirm that you may continue to rely on this Certificate as being true and correct on the day that you issue the Opinion unless I shall have previously notified you personally to the contrary.

[signature page follows]

Signature:	/s/ LI YUAN
Name: LI YUAN
Title: Director