Abstract: For the retaining wall rotating around the base and being backfilled by non-sticky earth with horizontal surface, we derive the active earth pressure formula under non-limit state through horizontal slice method by considering the exercising degree of soil friction angle and variation of earth pressure coefficient. The results show that the active earth pressure behind the wall under non-limit state is a concave curve. The larger the wall rotating amplitude is, the larger the curve curvature of earth pressure is,  the less the total soil pressure is , and the closer the action point is to the wall bottom. The analytical results are in accordance with related field test results, verifying the presented formula.