To calculate the earth pressure in saturated soil mass subjected to earthquake forces and groundwater seepage,two cases,in which the seepage states are steady but the shapes of the flow lines are different,are investigated.The two cases are Case 1,in which the flow line is vertical downward,and Case 2,in which the flow line is curve toward retaining wall.Based on the pseudo-static method and Coulombs theory,the formula to calculate the seismic active earth pressures in Cases 1 and 2 is proposed.The comparison of the results with the published work indicates that the suggested formula is reasonable.The influence of the soil effective internal friction angle on the seismic active earth pressure is also discussed.The results indicate that the total seismic active earth pressure is decreasing nonlinearly with the increase of the soil effective internal friction angle.And the decrement of the total seismic active earth pressure in Case 2 is larger than that in Case 1.