Abstract: This paper argues that social mobility and stratification of peasants’children can be a good indicator measuring social openness of China under a rapid industrialization and urbanization circumstance. In an urbanization framework, their social mobility can be operationalized as transition to nonagricultural occupations and change to urban household registration (hukou) holders. Peasants’children here include farmers, rural migrants and those who have changed their hukou type from rural to urban. They have similar original social backgrounds but are differentiated by occupations and household registration types. Based on national representative samples of this population, the paper tries to provide a more complete picture about the openness of Chinese society than conventional studies of occupational mobility based on city samples and labor studies on migrant workers did. CGSS data is used to describe the probability of occupational transition and citizenship transition of peasants’children in different periods and ages. It finds that the occupational transition pace is quite faster than the transition of citizenship. The probability for peasants’children to earn urban citizenship is stably low. The gap between occupational transition and citizenship transition is becoming larger and larger. It also finds that the traditional channels through which peasants’children can become registered urban citizens are becoming narrower. The rapid expansion of urbanization brings in new chances and channels. Based on these, several hypotheses about the changing of mobility mechanism are developed. The main one is that the distribution of citizenship transition chances is relatively fair and equal. These hypotheses then are tested by comparing the regression coefficients of factors influencing these transitions in different jobcohorts with CGSS data. It shows that the occupational transition is highly influenced by the family background. The effect of education is becoming smaller and smaller. Meanwhile, the distribution of limited citizenship transition chances is relatively fair. Education is always the main factor that differentiates the probability of citizenship transition. It concludes that the openness of Chinese society is a complex issue. It is quite open in terms of the Chinese peasants’ children’s opportunities to find a nonagricultural job. But the process is highly influenced by the family background and parents’social economic status, which is especially the case for getting good jobs. Meanwhile there are limited chances for peasants’children to change their citizenship type, but the distribution of the chance is relatively stable and fair. The speeding up of “citizenization of people” (changing their household registration type, giving them equal urban citizenship and public welfare) driven by the government of China will lead to expansion of citizenship transition chance, but the core of openness, fairness, is still a problem.

Key words: peasants’children, urbanization, nonagricultural transition of occupation, transition to registeredurban citizen