Research conclusions: Staring with the system theory，the decision － making evaluation index system is established for the bidding scheme for the BOT project of passenger dedicated line and the evaluation is made with grey situation decision － making model． In the railway BOT project，there are lots of factors to influence the project risks and it is difficult to determine the relations among the influence factors． Now the commonly － used evaluation methods include thecomprehensive fuzzy evaluation model，ANN model and so on． These methods have their own advantages，but also they have disadvantages． With these methods，the differences of the comprehensive optimization index values are not obvious of various schemes and the model results are affected by the objective factors． Especially，with these methods，the high risks of railway BOT project can not be considered． The result of the model presented in this paper can not be affected by the objective factors，so this model is more accurate and effective in revealing the differences of the comprehensive optimization index values of various bidding schemes． This model has universal property，so it can be available for BOT projects of the highway and power supply．