At present, the related research on the causes of "left-behind children" is very seldom. Most of literatures are simply summarized as two points: farmers need to survive, and it is the choice of the subject; the second is the inevitable process of China's economic and social development and the objective necessity. In this paper, Bourdieu's Practical Theory, such as Field, capital and habitus three elements, is analyzed and the behavior of workers is explained. It is considered that the phenomenon of left-behind children appearing in large scale in China is not only a problem of economic development, but also a special habitus of "working", which is not simply the individual choice behavior of the parents of left-behind children.