Abstract: With respect to multiple attribute decision making problems in which the attribute weight information is incomplete and the attribute values are intuitionistic trapezoid fuzzy numbers, this paper gives a new method based on the score function of intuitionistic trapezoid fuzzy numbers. With respect to multiple attribute decision making problems in which the attribute weight information is incomplete and the attribute values are intuitionistic trapezoid fuzzy numbers, and how decisions by projection method for nonlinear planning model, the authors use software of mathematics to attain each attribute weight and ranking with the projection rate on the ideal score to solution. Finally, a numerical example is provided to illustrate the effectiveness of the method.