Peasants in contemporary China take around seventy percents of the total population, and thus the tone of many social problems is still determined by peasants. Now the problem that peasants go out for employment is becoming more and more important in contemporary China studies. The basic causes of peasants’ outgo for employment are closely linked to the economic and social development in China, and to Chinese history and culture. It is the outcome of survival pressure and rational choice. Rational choice comprises of three levels: survival rational choice, economic rational choice and social rational choice. Furthermore, the survival rational choice is the fundamental level, and only when the survival rational choice is fully realized can economic rational choice and social rational choice be produced. Nowadays the outgoing peasants represent a progress from survival rational choice to social rational choice or economic rational choice under the condition of more flexible institutions.