Abstract: The sand liquefaction problem has been one of the important topics in soil dynamics and geotechnical earthquake engineering. Combined with a liquefied sand ground treatment project of the Middle Route Project of South-to-North Water Diversion, according to the orthogonal design method, 9 reinforcement treatment programs are designed, which take three parameters of pile diameter, pile length and pile spacing as the three factors of the orthogonal tests, and each factor takes 3 levels further. Dynamic numerical analysis is conducted on the liquefied sand ground treatment with compacted gravel piles. And the excess pore water pressure and pore pressure ratio in the saturated sand foundation are obtained under different reinforcement programs. How the pile diameter, pile length and pile spacing affect the excess pore pressures and the excess pore pressure ratio is analyzed by means of the range method. The intuitive analysis charts of how various factors affect the excess pore pressures and excess pore pressure ratio are drawn. Finally, the optimal reinforcement with compacted gravel piles can be obtained.