Steel concrete composite bridge has been widely used in recent years, it can take full advantage of the characteristics of the steel and concrete, greatly saves the cost of bridge. Traditional composite structure, pouring concrete in the erection of steel beams, this method of construction causing long bridge construction period and the place concrete quality is not reliable. Against the disadvantages, Scholars put forward the concept of prefabricated composite structures. According to the analysis of its stress, this paper put forward the Finite element modeling method of Prefabricated Steel Concrete Composite Bridge, it can accurately simulate each construction stage.