The probability of a number of basic events itself was uncertain and fuzzy when the traditional FTA method was used in the practical quantitative analysis quite. It was difficult to obtain the exact probability from failures, which violated the premise of exact probability selected. In order to solve the traditional fault tree analysis (FTA) of the probability the basic event fuzzy and uncertain problems, the concept of fuzzy theory were introduced, and the fuzzy probability was used to deal with the basic events lack of statistical data. The basic events of fuzzy probability were described by using a clear triangular fuzzy number, the fuzzy probability distribution of top event layer by layer was obtained, and the fuzzy importance of each basic event was determined by using fuzzy numbers value method. And the sort of top event of failure factors was obtained, the main factors influencing the accident were identified and effective measures from fundamentally preventive and the key points to control the top event were proposed.