"One patent for one invention" is an established doctrine under the Chinese patent regime. However, a recent decision delivered by the Supreme People's Court made it possible for one invention to have more than one patents.

Under the Chinese Patent Law, there are three types of patent: patent for invention, patent for utility model and patent for design. There are two major differences between patent for invention and other two types of patent. Firstly, the duration of patent for invention is twenty years, and that for utility model and design is ten years, counted from the filing date in China. Secondly, it takes substantially less time to grant a patent for utility model or design as there is no substantive examination for such applications. Therefore, it is possible to file simultaneously one application for invention and another one for utility model with respect to one invention, to take advantage of the differences. The Examination Guidelines approves such practice on the condition that there will be no more than one concurrently valid patent. However, the practice is challenged by a long-lasting invalidation case.

Mr. Shu filed with the Patent Office an application for patent for utility model on February 7, 1991 and the application was granted a patent on February 26, 1992. On February 22, 1992, Mr. Shu filed an application for patent for invention for the same invention and the application was granted a patent on October 13, 1999. On February 8, 1999, his patent for utility model expired (Under the old Patent Law, a utility model patent has maximum term of 8 years).

On December 22, 2000, a Chinese company filed an invalidation petition with the Patent Reexamination Board against Mr. Shu's patent for invention. The petition was denied on the ground that there was no co-existence of patent for invention and patent for utility model. The company appealed the decision to Beijing No. 1 Intermediate People's Court. The court upheld the decision of the Board. However, the appellate court, the Beijing High People's Court, overturned the decision. In the decision made in March 2003, the court held that once a patent for utility model was terminated, the subject matter of the patent became part of the public domain allowing free use by the public, which can not be granted a patent right again. The granting of the application for patent for invention was in violation of the "one patent for one invention" principle. Dissatisfied with the decision, both the Patent Reexamination Board and Mr. Shu lodged re-trial petition with the Supreme People's Court.

On July 14, 2008, the Supreme People's Court made its decision on the case, reversing the decision of the Beijing High People's Court. According to the court, the principle of "one patent for one invention" means that it is not allowed to have two or more concurrently valid patents over one invention. Once a patent is terminated, it doesn't necessarily mean the subject matter of the patent become part of the public domain. The court is of the opinion that two patents relate to identical inventions only if protection scope claimed in one patent is identical with that of another one.