Abstract: The calculation of earth pressure of flexible retaining wall under earthquake ground motion is a complex problem, and the relevant method for calculating the earth pressure is still not mature and conservative. In order to calculate the active earth pressure of soil-nailing retaining structure under earthquake ground motion accurately and reasonably based on the energy method and the limit equilibrium method, a model for the seismic active earth pressure is established, in which the sliding surface is considered as a plane, and the formula is obtained considering the influence of the role of soil-nailing retaining structure on the earth pressure. Based on an engineering example, the results obtained from the above formula are compared with those obtained from the existing norms and methods, and parametric analysis is carried out, and then some practical results are obtained. The results show that the calculated earth pressures are smaller than those from other methods. The existence of soil nails can effectively reduce the lateral pressure of supporting structures under earthquake ground motions and make the sliding surface slowly move to the wall back. The proposed method considering the role of soil nailing is more reasonable and agrees with the actual engineering. It may provide some valuable references for the construction, optimization and anti-seismic design of soil-nailing retaining structures.