China's patent law and its implementing rules stipulate that the date when the patent administrative department in the State Council receives the patent application documents is the date of patent application. If the application documents are mailed, the postmark date of mailing shall be the application date. This provision shows that there are two methods to determine the date of patent application in China. The first way is to submit the patent application documents that meet the specifications directly to the China National Intellectual Property Administration Patent Office and its established agency, and the date when the accepting department receives the patent application documents is the application date; After receiving the relevant patent application documents, the accepting department shall issue an acceptance notice to the patent applicant, indicating the date and number of the patent application. The second way is to use the postmark date of qualified patent application documents as the application date through the post office. However, if the postmark date sent is unclear and it is impossible to determine the postmark date, unless the patent applicant can provide proof, the date received by the accepting department shall be the application date.