Soil arching is the key factor of load transfer in a pile-supported embankment. Its development and stability under cyclic loading will directly affect the bearing capacity of the embankment. Based on the laboratory model test, a series of particle flow numerical models of the pile-supported embankment are established by using PFC2D software, and the correctness of the models verified by the laboratory model test results. Based on the discrete element numerical models, the embankment is subjected to vehicle cyclic loads simulated by sinusoidal wave loads, and the development and reduction of soil arching in pile-supported embankment under cyclic loading are analyzed. The numerical results show that the ratio of embankment height to pile spacing, cyclic load amplitude，and frequency all affect the soil arching in the piled embankment, while the variation of the ratio of embankment height to pile spacing significantly influences the soil arching reduction coefficient. The ratio of the embankment height to the pile spacing is an important factor affecting the stability of the soil arching in the piled embankment subjected to cyclic load. Hence, the expression of the soil arching reduction coefficient is derived based on the analysis and curve fitting of discrete element numerical results by taking those factors into consideration.