Under the background of accurate anti-poverty project, the whole country is playing a fight against poverty, and the results have been obvious to all. Social assistance, as the last line of protection and safety nets for social security, plays an important role in accurate anti-poverty project to provide help for poor households who without labor capacity and poor people who has temporary difficulties. Based on the investigation of Zhenfeng County of Guizhou Province, this paper argues that the minimum guarantee effect of social assistance system is mainly embodied in three aspects: the government provide the capital protection for the subsistence allowances and the poor people, the medical assistance, the education assistance.