This paper performs stochastic seismic analysis of a geosynthetic-reinforced soil slope under random ground motions. The paper employs the probability density evolution method (PDEM) to carry out the probabilistic analysis. The stochastic seismic ground motions are generated using the random function based spectral representation method. The results show that for the same seismic deformation the middle to bottom reinforcement layers generally have higher probability of failure than other reinforcement layers. Thus, an increase in reinforcement strength in the middle to bottom part of the reinforced soil slope may be needed in order to keep the slope from large displacement of failure. The results indicate that the PDEM is an efficient method to carry out the stochastic seismic analysis of geosynthetic-reinforced soil slopes.