Compared with that in other countries, the issue of fertility in China is more complicated because of its restriction policy or system. Several major hypotheses have been proposed to explain and predict the impact of migration on China’s fertility regardless of China’s real situation. Therefore, this paper analyzes the impact of migration on fertility considering China’s underlying restrictions using the data from the Chinese General Social Survey carried out in 2008. The social class in this study was divided into two, namely urban class and rural class. By building the 2�נ2 mobility tables and the diagonal mobility model, the study determined the impact of migration on fertility and analyzed the influence of some restrictions, such as family planning, traditional fertility concept, and household registration system. Results show that migration greatly affects fertility: upward migration (i.e., from rural to urban) may decrease the fertility, whereas downward migration (i.e., from urban to rural) may increase it. The degree of decline on fertility is greater than that of increase. Family planning still plays a role in fertility decline. Traditional concepts on fertility, for example, bringing up sons to take care of parents in their old age and preferring boys to girls, are anchored on the people’s mind, which is detrimental to the stability of the fertility rate. Moreover, the household registration system primarily influences the fertility behavior of temporary migration, with a negative relationship between them.