This paper starts with the improvement of bidding evaluation, and puts forward the viewpoint of comprehensive evaluation directing at the single domestic evaluation approach. It made analog and analysis on the existing domestic evaluation approach and brought forward an evaluation mode combining two ways. Then it built the evaluation index system according to the multiple-input and multiple-output, characteristics of the decision-making unit. The article introduced information entropy to the comprehensive evaluation of the bidding ability of the construction companies, strictly defined the various weights of each index to make them the priority among priorities, and further reduced the human factors in the evaluation and decreased the randomness to eliminate the defects in the process of evaluation in construction projects. This paper enhanced the efficiency of bidding evaluation based on the objective and scientific evaluation on the decision-making unit, and verified its effects.