Legal analysis: Patent opposition is a review system that allows anyone in the society to raise objections to the patent application within the legal period after the patent application is announced. The patent opposition procedure is as follows: 1. The opposition applicant submits a letter of objection and relevant evidence materials to the Patent Office; 2. The Patent Office sends a copy of the objection letter to the opposed patent applicant; 3. The opposed party makes a written reply; etc.
Legal basis: "Patent Law of the People's Republic of China" Article 35 Within three years from the filing date of an invention patent application, the patent administration department of the State Council may, upon request submitted by the applicant at any time, The application shall be subject to substantive examination; if the applicant fails to request substantive examination within the time limit without justifiable reasons, the application shall be deemed to have been withdrawn. When the patent administration department of the State Council deems it necessary, it may conduct a substantive examination of an invention patent application on its own.