Basal boundary line of class structure in China lies on the differentiation between peasants and non peasants. Occupational mobility of peasants means breaking through this base line. But now there is very little study of farmer labor mobility focusing on the life course of peasants’ mobility in sociology and economics. The reason lies in two sides: firstly, most economic studies are based on theories of surplus labor transition, and concentrated on the issues of mobility reason, mobility size and so on. Secondly, sociological studies focused on the well being of peasant workers in the city. In this paper, the author centralizes his discussion on the transition rate of peasants’ occupational mobility, and mainly analyzes its institutional condition, human capital, and life course of the surplus labor. Drawing on a strict random sampling data, which covers all over China in 1996, the author also challenges the comparing interest theory and human capital theory in the field of surplus labor mobility.