Developing modern agriculture is the initial task in building new socialist countryside,and it is the inevitable demand to guide the construction of the countryside with the scientific development conception,which is also an important opportunity to the sustainable and healthy development for private enterprises.This paper analyzed the status and function of private enterprises in the development of modern agriculture and the construction of new socialist countryside.This paper also revealed some problems encountered by private enterprises in their development and put forward some countermeasures to promote the development of private enterprises,develop modern agriculture and build new socialist countryside.