Investment of power transmission and transformation project is of profits, as well as a kind of public service. Good post-evaluation of power transmission and transformation project can provide references for subsequent power grid construction, as well as improve enterprise benefits and social benefits. Post-evaluation of power transmission and transformation project is of characteristics of comprehensiveness, multi-layer and fuzziness. Based on its characteristics, this paper establishes the index system of post-evaluation. In evaluation methods，fuzzy hierarchy comprehensive evaluation is selected to build fuzzy comprehensive evaluation model of power transmission and transformation project, which is analyzed specifically by applying one case study. The results show that this model can effectively evaluate the economic benefits of the power transmission and transformation project．