Legal basis: According to Article 42 of the Patent Law of People's Republic of China (PRC), the term of invention patent is 20 years, the term of utility model patent is 10 year, and the term of design patent is 15 year, all of which are counted from the date of application. Where a patent for invention is granted for four years from the date of application for a patent for invention and three years from the date of request for substantive examination, the patent administration department of the State Council shall, at the request of the patentee, compensate for the unreasonable delay of the invention patent in the process of authorization, except for the unreasonable delay caused by the applicant. In order to compensate for the time occupied by the review and approval of new drugs, the patent administration department of the State Council shall compensate the patentee for the patent term of new drug-related invention patents that have been approved for listing in China. The compensation period shall not exceed five years, and the total effective patent right period after the new drug is approved for marketing shall not exceed fourteen years.