Abstract：On the basis of the assumption that minor principal stress trace is parabola，the soil arching behind rigid retaining wall is analyzed. The coefficients of active earth and water pressure(AWP) and the horizontal differential element interlayer are obtained. The two-dimensional Laplace equation of the stable seepage field behind rigid retaining wall is also established during continuous rainfall. Based on the analysis of considering，the calculating model of AWP is presented. The formulas of the resultant force，the point of resultant force and the practical coefficient of AWP are proposed. The result of theory analysis shows that the theory value is consisted with the experimental value. When the soil arching and the stable seepage are considered，the distribution of AWP is nonlinear，and the resultant force increases，and the point of resultant force is higher. Therefore，the adverse effect of the soil arching and seepage on the safety of rigid retaining wall should be highly emphasized in the engineering practice. The practical coefficient method of AWP is available for the simplified and practical calculating method of AWP during continuous rainfall.
