China did not join the Proliferation Security Initiative due to deep legal and policy considerations. China now has sufficient reasons to reappraise its existing stance in light of the establishment and continuous development of a positive, cooperative and comprehensive Sino-U.S. relationship, institutionalization of the PSI by U.S. President Barack Obama, and new changes in nuclear nonproliferation and disarmament. China’s participation in the PSI will be much more useful in enhancing the construction of international nonproliferation systems rather than remaining disengaged. Now it is the time for China to make the political decision and participate in the PSI.