In the process of EPC projects bidding and tendering, the most effective way to eliminate unfair competition is to examine the qualifications of tenders and to evaluate the biddings. Bidding appraisal plays a key role in the EPC projects, which will directly affect the results of the investment projects. Evaluation method is a key factor for an objective and correct evaluation. There are traditional methods of risk analysis such as survey and experts' points, net present value (NPV), analytic hierarchy process (AHP), RBF Neural Network, sensitivity analysis, etc. However, traditional evaluation methods of bidding have the defect of determining the weights, merely according to the subjective judgments of experts or decision makers. In this paper, an entropy-weight-based TOPSIS method is proposed to decide the weights. According to our method, the weight coefficients in TOPSIS method are given by means of entropy coefficient. Our method has the advantages of combining experts' subjective opinions with objective situations and the combining quantitative analyses with qualitative analyses. The proposed method is applied to evaluate information system integration solutions and numerical illustrations proved the effectiveness of our method.