In this paper, with China's economic and social development, energy shortage and environmental deterioration has become an acute problem. The promotion of green public building, palys a veryimportant role for building a resourceconserving and environment-friendly society in China. This paper analysis on the connotation of value engineering and green public building, demonstrates the value engineering to the necessity of investment decision of green public building, and describes its application process. In particular, the environmental benefits, the individual benefits, social benefits are as a function of green public building, use the analytic hierarchy process and fuzzy comprehensive evaluation to quantitative analysis each function index, ultimately use value engineering to make investment decisions for green public building.