Abstract: In order to solve energy crisis and environment pollution, the clean energy based distributed generation is access into power system with large scale. However, the output of distributed generation mainly depends on uncertain weather conditions and it is necessary to take its uncertainty into traditional power system operation risk assessment. In this paper a review on risk based assessment method for power system operation considering the influence of distributed generation is offered. It includes state selecting method, component fault model, distributed generation output model, common risk indices and load model. The proposed method could reduce the effect from distributed generation uncertainty and enhance its penetration proportion into power system in valid.