When using the National Concrete Masonry Association method of studying the seismic performance of vertically reinforced earth-retaining walls, the external power of the wall could not be comprehensively calculated, and there was a high deviation in the results of the seismic performance analysis. Therefore, the limit analysis method was used in this paper to analyze the failure mode of a vertically reinforced earth-retaining wall, and an expression of the movement limit of the retaining wall was obtained. According to the expression, the external power of the retaining wall (including the external power of the soil weight and the external power of earthquake action) was calculated, and its seismic performance analyzed. The experimental results showed that the maximum external power of each layer of the vertically reinforced earth-retaining wall was 18.5 kN·m and 20 kN·m, respectively, which did not vary significantly from the actual maximum external power (18 kN·m). The study indicates that seismic performance analysis with this method is consistent with actual conditions and can be applied to actual projects.