EPS composite soil is a new kind of lightweight soil. As the fill material for the embankment, it has enormous advantages. Based on a known case, a finite element model was established, and its efficiency and rationality were verified. The established model was used to analyze the mechanical behaviors of the embankment considering EPS composite soil and the conventional soil. It was concluded that EPS composite soil can effectively reduce the settlement, soil pressure and excess pore water pressure and so as to improve the safety of the ground. It will have widespread applications.