The post evaluation is the last and indispensable procedure of the project life cycle, but the operation of the method is too complex and needs heavy computation, so it is difficult for implementation. The key to the method for the comprehensive assessment for the post evaluation of the project is to establish a system that both meets the requirement of the post evaluation on the project and provides the evaluation index and weight coefficient for the project objective. Also, the post evaluation of the sustainability and the degree of success can be conducted by the system. The method was discussed by integrating combination evaluation method with the success degree method and modifying and taking the secondary development project as the case. The method is characterized of simple, reliable, comparable, objective and operable. The simple method can be applied to the non-detail post evaluation and it is easy to be popularized and applied.