The invention discloses a method for computing a fault probability of a transformer bushing based on fuzzy set values. The method comprises the steps that (A) fault factors of the electric transformer bushing are determined; (B) an occurrence probability of each fault factor is determined; (C) a fuzzy set value statistic method is used to determine the weight of each fault factor; and (D) the fault probability of the electric transformer bushing can be computed according to the occurrence probability and the weight of each fault factor. According to the method, the manner of reliability is used to represent many uncertain factors existing in the transformer bushing; deficiency and wrong judgment of information will not be generated; and actual situations can be reflected more authentically and comprehensively.