Legal basis: People's Republic of China (PRC) Patent Law.
Article 28 The date when the patent administrative department of the State Council receives the patent application documents is:
1. If the applicant submits the documents to the Patent Office in person, the date when the Patent Office receives the documents is the filing date;
2. If the application documents are mailed, the postmark date of mailing shall be the application date.
3. If the postmark is vague or illegible, the Patent Office will notify the applicant. If the applicant can submit evidence of the exact date when the application documents were sent in the post office, the date of sending the documents will be the application date;
4. Where the applicant can't provide relevant supporting documents, the date of receipt of the application documents by the patent administrative department of the State Council shall be the filing date.
Article 42 The term of patent right for invention is 20 years, and the term of patent right for utility model and patent right for design is 10 years, counting from the date of application.