Abstract: Most current decision methods of fixed weight problems rely on decision-making matrix and ignoring the background. Aiming at these problems, the method of case-based reasoning was fused into the intuitionistic fuzzy decision making problem. At first,according to the connotation of intuitionistic fuzzy numbers, a similarity formula was proposed. By combination of case-based reasoning model with similarity measure, the optimal weight and radius of classification were obtained, and by which the best alternative was gained.Finally, through case analysis details the advantages of this method were summarized as follows: this method not only took the decision data into consideration but also expert's advice, and made the decision results more consistent with the reality, and put forward a new idea to solve the problem of intuitionistic fuzzy decision making problems.

Key words: decision making, intuitionistic fuzzy number, similarity degree, case-based reasoning