When does the transfer of patent right take effect?

It shall take effect as of the date of registration with the patent administration department of the State Council.

Where the third paragraph of Article 10 of the Patent Law of People's Republic of China (PRC) transfers the right to apply for a patent or the patent right, the parties concerned shall conclude a written contract and register it with the patent administration department of the State Council, and the patent administration department of the State Council shall make an announcement. The transfer of the right to apply for a patent or the patent right shall take effect from the date of registration.