Abstract: The reliability analysis of certainty eventfuzzy probability system was obtained by the combination method of the fuzzy set theory and homogeneous Semi-Markov process. The mathematical algorithm of triangular fuzzy number was defined, and an approach was also presented to convert the component failure probability value to a triangular fuzzy number from reliability database of nuclear power components, and fuzzy probability homogeneous Semi-Markov arithmetic model was derived to calculate system state probability. The arithmetic of the fuzzy kernel matrix was also presented. The results by an actual example show that this method can do uncertainty analysis based on the general data, so it can make up the imperfection of the analysis results obtained by using the point estimate value only.