Legal basis:
Article 67 of the Patent Law of People's Republic of China (PRC) In a patent infringement dispute, if the accused infringer has evidence to prove that the technology or design implemented by him belongs to the existing technology or design, it does not constitute patent infringement.
Article 75 Any of the following circumstances shall not be regarded as infringement of the patent right: (1) A patented product or a product directly obtained by a patented method is used, promised to be sold, sold or imported by the patentee or a unit or individual licensed by him; (2) Having manufactured the same product, used the same method or made necessary preparations for its manufacture and use before the patent application date, and continuing to manufacture and use it only within the original scope; (3) Foreign means of transport temporarily passing through China's territorial waters and airspace use the relevant patents in their devices and equipment for their own needs in accordance with the agreements signed between their countries and China or international treaties to which they are both parties, or on the principle of reciprocity; (four) the use of relevant patents for scientific research and experiments; (5) manufacturing, using or importing patented drugs or patented medical devices for the purpose of providing information required for administrative examination and approval, or manufacturing or importing patented drugs or patented medical devices exclusively for them.