In this paper, authors explored the SEM technique to calculate the importance weight of evaluation indexes system for construction project success. Project success is a foundation to manage and control current projects, and to plan and orient future projects. The SEM model, along with factor analysis, represents a new approach to weighting the importance role of indexes system that has not been discussed before. Weight assignment plays a very important role in the evaluation index system. Some methods and approaches were applied in weight assignment. Each of them has its own advantages and disadvantages. By doing fitting index, this paper provided a fit of model and assigned quantitative weight indexes system. The results of this paper suggested a system of ten indicators and forty-six criteria to evaluate construction project success. In this system, the importance of criteria related to environment, safety issue, and communication among project was stressed. They rank in the top of the project evaluation model. This implies a tendency in respondents’ opinions about the importance level of these issues. Up to now, a complete system included both list of indexes and importance weight of them were achieved. So, project success can be quantitative evaluation. However, this system should be applied in a real construction project and the feedback obtained to optimize; this is a part of our future mission. Ten indicators and 46 criteria is a complex system to evaluate project success. It helps to describe the project comprehensively. However, it make the evaluator encounter a little difficulties. So, future researches may concentrate on this issue to optimize the evaluation system.