Under normal circumstances, the Patent Office shall conduct a preliminary examination after receiving an application for a patent for invention, utility model and design. The preliminary examination is the first stage of the patent examination and approval procedure, which mainly deals with the received patent application documents to prepare for future publication or announcement. The preliminary examination mainly includes two contents: (1) examination of the format of patent application documents: checking whether the patent application documents are complete and the format is in compliance with the regulations, for example, whether all the columns in the request are complete and correct, and whether the application fee has been paid according to the regulations. Those who pass the examination will be notified by the Patent Office (usually within one month) and get the patent application number. (2) Examination of the contents of the patent application: whether it "violates national laws, social morality or harms public interests"; Whether it clearly falls within the scope of "no patent right is granted" as stipulated in Article 25 of the Patent Law, whether it belongs to national security or major interests, it should be kept confidential.
Substantive examination is the second stage of the examination and approval procedure for invention patent application, which mainly determines the patentability of an invention from a technical point of view, that is, whether it meets the requirements of novelty, creativity and practicality stipulated in the patent law. Generally speaking, the substantive examination begins after the applicant submits a request for substantive examination to the Patent Office and pays the examination fee. However, when the Patent Office deems it necessary, it may examine the application for a patent for invention on its own.