Bidding decision is a complex issue that refers to unstructured multi-level group decision making and game theory. For analyzing the process of project biding, a mathematical statistics analysis method, based on the quotation level and bidding rate, was proposed. Based on the discussion of the mathematical curve fitting, the method of regression equation calculation based on the significance of linear regression equation, the mathematical model of quotation level and winning rate was constructed. According to the case study, the designed method improved the bidding rate of biding contractor and reduced the blindness of bidding decision. therefore, it was concluded that this method is scientific and effective.