With respect to multiple attribute decision making (MADM) problems in which the attribute value takes the form of intuitionistic trapezoidal fuzzy number, a new decision making analysis method is developed. Firstly, some operational laws and expected values of intuitionistic trapezoidal fuzzy numbers, and distance between two intuitionistic trapezoidal fuzzy numbers, are introduced, and the comparison method for the intuitionistic trapezoidal fuzzy numbers is proposed. Then, combined the power aggregation operator and the generalized aggregation operator, a power generalized average (PGA) operator is proposed, and some properties of the PGA operator, such as idempotency, boundary, commutativity, etc., are studied. At the same time, some special cases of the generalized parameters in PGA operator are analyzed. Furthermore, an intuitionistic trapezoidal fuzzy power generalized weighted average (ITFPGWA) operator is also proposed for the intuitionistic trapezoidal fuzzy information, and some properties of the ITFPGWA operator and an approach to deal with group decision making problems under intuitionistic trapezoidal fuzzy information based on the ITFPGWA operator are given. Finally, an illustrative example is given to illustrate the decision-making steps, and to demonstrate its practicality and effectiveness.