The evaluation of the effect of landslide hazards prevention and control is a systematic project. Based on a great deal of field survey, an evaluation index system including 5 first-level indexes (basic element of landslide, control design, construction organization, stability and treatment benefit) and 11 second-level indexes are established. Based on the comprehensive fuzzy hierarchy estimation, the weight of each index is determined and the maximum subordinate degree of control effect is calculated. Taking the case of Liujiabao landslide in the Three Gorges Reservoir as an example, the calculation shows that the effect of control engineering is excellent; this is consistent with the actual situation, and the reliability of this method is verified.