How long does it take to examine the substance of the invention patent?

Legal analysis: The time for patent substantive examination is uncertain, generally 6- 18 months, which depends on the content of the invention, the examiner's understanding of the invention, the examiner's work arrangement and the time for documents to be transmitted back and forth between the examiner and the applicant or his agent.

If the applicant cannot reply to the notice of examination opinions within the specified time, he may also apply for an extension before the time limit specified in the notice of examination opinions. He can apply for an extension of two months at a time, with a maximum of two extensions.

Legal basis: Article 35 of the Patent Law of People's Republic of China (PRC). Within three years from the date of filing, the patent administration department in the State Council may examine the application according to the request made by the applicant at any time. If the applicant fails to request substantive examination within the time limit without justifiable reasons, the application shall be deemed to have been withdrawn.