Currently, there is a large amount of earth dams should be reinforced because of the running incessantly in a long period in our country. And the anti-seepage evaluation is an extremely critical and indispensable index to scrutinize the reinforcement effect of earth dam comprehensively. According to the real engineering conditions of the dam, the finite element seepage analysis method is used to compute the seepage characteristics in the Fengchan reservoir before and after the reinforcement in this paper. The results show that the effect of the anti-seepage system is well for adopting the concrete slope protection and concrete anti-seepage wall. The seepage state of foundation and dam body is improved evidently. The seepage gradient and seepage quantity of each material zone reduce significantly and meet the standard requirement of specification.