With the rapid process of China’s urbanization, the pattern of social interests, social class position, social gap between the rich and the poor, as well as criminal rates have all changed. With the increasing number of migrant farmers in cities, migrant farmers have become the city's biggest crime subject because of their different cultural qualities, legal consciousness, and social cultural environment and so on. And the border of urban and rural has become the city's most concentrated area of the crime. The Constitution of our country hasn’t set citizens' right of free migration, which is the significant cause of the crime as a result of the lack of equal rights for the migrants. The increasing crimes of the floating population have severely hampered the process of China’s modernization and legalization. To solve the problem of crime in China's urbanization process from the deep level, it must base on China's actual conditions, establish the right of free migration to ensure the equal rights of migrant farmers, and make feasible criminal policy and social policy for China's urbanization road.