Facing all kinds of risks in the field of social assistance, some local governments increasingly appeal to commercial insurance for help. In the medical and nursing care, natural disasters, accidents and other fields, commercial insurance more and more involved in social assistance. Based on the analysis of the present situation of the commercial insurance cooperative social assistance, this paper explores the mechanism of commercial insurance cooperative social assistance. It is believed that the current social assistance is still in the government's own burden, so the financial burden is very heavy. The multiple participation mechanism of social assistance should be among government and enterprise or community.