Abstract: Referring to the question that it is hard to determine the index weight of comprehensive evaluation for the selection of engineering materials, combined weighted method based on weight confidence is put forward on the base of analyzing the theory and shortcoming of existing combined weighted method. Taking the choice of storage pot material under low temperature working condition as an example, subjective, objective and intelligent weights of eight kinds of evaluation indices, obtained by analytic hierarchy process, improved entropy method and back propagation network respectively, were combined with combined weighted method proposed above. Ten kinds of candidate materials were evaluated according to improved technique for order preference by similarity to ideal solution (ITOPSIS) with the combined weights obtained. The results show that the 301 stainless steel is the best storage pot material under low temperature working condition, this accords with industry practice. All above show that the weights of evaluation indices for engineering materials determined by the combined weighted method are reasonable and feasible.