Abstract: Risk analysis is one of the important items of feasibility stu-dy,concept research and project review on a space system with high risk.Considering the complexity involved in the application of the syntheticanalysis methods,such as GERT,VERT,RISNET and SLAM,the paperpresents three rapid and convenient risk analysis methods,e.g.IsoriskContour Method,Risk Parameter Method and Probability Event Analysiswhich are suitable to the engineers and technicians,especially the mana-gers,for easy using.