Abstract: A fuzzy reliability allocation method for engine was proposed based on multi-field experts' knowledge.In this method,fuzzy set theory was used to decrease subjective preferences of decision makers as well as fuzzy and uncertain factors in reliability allocation process.The mathematical model of fuzzy reliability allocation for engine was constructed based on the analysis of influential factors to engine reliability allocation.A fuzzy evaluation matrix method was proposed to determine the weights of the influential factors in which the triangular fuzzy numbers were utilized to substitute the scaling scheme of conventional analytic hierarchy process.Experts' opinions and the risk index of the product development process were also taken into account in the method.An application example was used to verify effectiveness and feasibility of the proposed method.