In China, the limitation of action for patent infringement is two years, counting from the date when the patentee or interested party knows or should know about the infringement.
If the patentee fails to pay the appropriate royalties before the patent right is granted after the publication of the application for a patent for invention, the limitation period for the patentee to request payment of the royalties shall be two years, counting from the date when the patentee knows or should know that others are using his invention. However, if the patentee knows or should know on the date when the patent right is granted, it shall be counted from the date when the patent right is granted.