China has publicly rejected the legitimacy of the unilateral sanctions referenced in the question, while stopping short of announcing a specific operational decision regarding the reported Iranian flights to Guangzhou and Shanghai.
China has reaffirmed its opposition to unilateral sanctions following a U.S. warning over continued international services to Iranian airlines.
During a regular Foreign Ministry briefing on September 22, spokesperson Guo Jiakun was asked about U.S. Treasury Secretary Scott Bessent’s warning that countries providing landing or fuel services to Iranian airlines could be excluded from the U.S. dollar system. The question also referred to Iranian flights reportedly scheduled to arrive in Guangzhou and Shanghai.
Guo said China has consistently opposed unilateral sanctions that have no basis in international law and are not authorized by the United Nations Security Council. The Chinese Foreign Ministry did not separately confirm whether the specific Iranian flights mentioned in the question would be permitted to land.
https://www.mfa.gov.cn/fyrbt_673021/202609/t20260922_12028748.shtml