6-K

UNITED STATES

SECURITIES AND EXCHANGECOMMISSION

WASHINGTON, D.C. 20549

FORM 6-K

Report of Foreign PrivateIssuer

Pursuant to Rule 13a-16or 15d-16

of the Securities Exchange Act of 1934

FOR THE MONTH OF July 2025

COMMISSION FILE NUMBER: 001-33863

XINYUAN REAL ESTATE CO., LTD.

27/F, China Central Place, Tower II

79 Jianguo Road, Chaoyang District

Beijing 100025

People’s Republic of China

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F****x                             Form 40-F  ¨

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): ¨

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): ¨

On July 10, 2025, Xinyuan Real Estate Co., Ltd. (the “Company”) entered into a subscription agreement (the “Subscription Agreement”) with Central Plains Ltd. (the “Purchaser”) pursuant to which the Purchaser purchases from the Company and the Company issues to the Purchaser an aggregate of 15,339,280 common shares of the Company, par value $0.0001 per share (the “Common Shares”), at a purchase price of $0.10 per Common Share (the “Transaction”). The Supplemental Listing Application for the issuance was approved by NYSE on July 11, 2025.

The Common Shares have not been registered under the Securities Act of 1933, as amended (the “Securities Act”), or the securities laws of any state, and were offered and issued in reliance on exemptions from registration under the Securities Act, afforded by provisions of Section 4(a)(2) and Regulation S promulgated under the Securities Act.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.