In the view of the construction of green university throughout the world, this paper summarizes the principles, connotation and methods of the evaluation green university index system. An index system is established for assessment of green university, which contains the green concept, the green culture, the green research, the green education and the green campus. By applying the multi-level grey approach, the article tries to innovate the evaluation approach of green university and develop Green Star rating system. Taken Jiangnan university as a case study, a comprehensive evaluation model is employed to puts forward a feasible and useful way for green university evaluation.