Aiming at the multiattribute group decision making (MAGDM) problems with intervalvalued intuitionistic trapezoidal fuzzy numbers (IVITFN) and unknown weights of attributes and decision makers, a VIKOR method of multiattribute group decision making based on intervalvalued intuitionistic trapezoidal fuzzy numbers and the entropy measure is proposed. Firstly, the decision maker’s evaluation information is transformed into IVITFN decision matrixes, and then the IVITFNs in the decision matrixes are normalized; Secondly, the decision matrixes of multiple decision makers are aggregated into a comprehensive decision matrix by using the intervalvalued intuitionistic trapezoidal fuzzy Bonferroni mean (IVITFBM) operator; then the weights of each attribute in the comprehensive decision matrix are calculated by using entropy method, and the ranking is given and the decision is made based on VIKOR method. Finally, the effectiveness and feasibility of the method are verified by the case study and comparative analysis.