Abstract: This paper deals with the decision problem where the preference information is given as the form of trapezoidal fuzzy number reciprocal judgement matrix.Firstly,by utilizing the continuous interval argument OWA(COWA)operator,we introduce the expected value function concept of trapezoidal fuzzy number for ranking order,which is adjusted according to decision-maker's optimistic degree and more reasonable.Secondly,the trapezoidal fuzzy number complementary judgment matrixis transformed into the expected value complementary judgment matrix for deriving the priorities of alternatives.Then,the method to make sensitivity analysis for the results by decision-maker's optimistic degree is proposed.Finally,a numerical example is given to show the feasibility and effectiveness of the developed method.

Key words: trapezoidal fuzzy number reciprocal judgment matrix, COWA operator, expected value function