To attract project investment is the solution to the problem of lacking fund support in Western Areas and is the impeller of Go-West Campaign.Yet the investors often jib at it because of the environment risk. In order to optimize the investment environment and reduce the investor's risk alert psychology,this paper analyzes the project investment environment risks in Western Areas from three aspects(credit,linkage point,net structure) based on the social capital theory.The result shows that the capacity of Collective Social Capital is the crux of investment environment risks.Then the author advances four countermeasures to improve investment environment from two aspects: cognitive and structural social investment,which has the certain reality guiding sense for reducing the risks.