Abstract: The paper analyses the deformation and the force condition of the soil nailing wall during its step-by-step excavation. The universal analysis software FLAC for geotechnical engineering and the numerical stimulating method are used in the process of analysis. Comparing with the axial force calculation result of CEC97:98 and JGJ 120-99, the paper tells the limitation of the current code pointing out that the axial force of soil nailing is nor only associated with the soil pressure of the controlled soil layer but mainly correlated with the increasing of the trend of the relative displacement between soil nailing and soil which is because of the accumulated deformation during the step-by-step excavation process. The paper also suggested that the first row of soil nailing should be lengthened or the soil property should be improved to enhance the shoring effect and to intensify the joint action between the soil layer and the soil nailing.