Abstract: An effective risk evaluation method for virtual enterprise is proposed. Focused on the characteristics of the project organization mode and the uncertain information, by considering the effect of time on entire risk of virtual enterprise, the model of virtual enterprise risk evaluation is established based on program evaluation and review technique. The entire risk of the enterprise is described by the project complication probability under different project risk level while the relationship between the risk level and the process time of each process, the fuzzy risk level of each process, and the relationship between the risk level and the process time of the project are known. The example analysis demonstrates that the method is an effective management tool for virtual enterprise risk evaluation.