Abstract: Whether or not the forces act on the surface of soil nailing supports is always controversial. According to the Chinese specification, there are no forces acting on soil nailing surface, so the jet concrete surface is designed in terms of certain structure. In fact, the earth pressure on soil nailing has great effect on deformation of the foundation excavations and stress distribution of the wall, especially in deep foundation excavations in soft soil ground. Based on the concept of effective sliding force, and considering with the incremental method, the sliding wedge balance method is improved. Through this complex algorithm, the calculated results indicate that there are forces acting on soil nailing surface, and they are compared with the measured ones. It is shown that the proposed method is practical.