Abstract: Fuzzy group decision making method is widely used in various fields of politics, economy and social life, which can effectively avoid the decision-making mistakes caused by personal knowledge and experience. A multiple criteria sorting method in the group decision making context based on CI-TOPSIS is proposed for fuzzy intuition trapezoidal multiple criteria group decision making problems with incomplete information. Firstly,the trapezoidal intuitionistic fuzzy sets and generalized trapezoidal intuitionistic fuzzy geometric clustering operator are given considering the corresponding dependence attribute among group decision-making. Secondly, the TOPSIS operator based on discrete Choquet integral (CI-TOPSIS) is given, which is based on and the classification procedure of trapezoidal intuitionistic fuzzy multi-criteria group decision based on CI-TOPSIS is given, which is used to determine the information set with the most credible group consensus case, and gradually guide decision-makers to give some precise classification of all programs, give full consideration to fuzzy decision-making environment, decision-making preferences and level relationship of case-level comparison information. Finally, an investment decision examples is used to verify the proposed multiple criteria sorting method and show that it may overcome information omission, and retain the full information in the decision-making process, more suitable for the decision practice under intuition fuzzy group decision making environment, and it is a kind of very effective and scientific method, which can be applied to more decision-making areas. As well as, the conclusion of this paper is of great significance for effective solving the group decision-making problem of multi-person investment scheme.

Key words: multiple criteria sorting method, trapezoidal intuition fuzzy sets, CI-TOPSIS, case comparison information