Feasibility study of transportation infrastructure projects attaches importance to economic evaluation based on cost and traffic volume, but the comprehensive evaluation index system of financial, economic, social, environmental and safety benefit needs to be further constructed in order to serve the classification decision of transportation infrastructure projects represented by major railway projects. We adopt the the multi-dimensional and multi-round screening method of "case method + clustering method + expert investigation + rooted coding + reverse trial calculation" to construct it，which includes 5 first-level indexes, 11 second-level indexes and 18 third-level indexes. According to "limited public welfare", it is divided into internal and external benefit index, we construct the two-dimensional inde, and five kinds of classification decision criteria. Selecting railway projects in eastern，central and western China to test, The results are excellent, good and prudent, respectively corresponding to the classified decision suggestions of priority, moderate and timing construction. The index system and classification decision standard can better reflect the characteristics of different types and improve the scientific decision-making, which provides important reference value for the compilation of "Economic Evaluation Methods and Parameters of Railway Construction Projects (fourth edition).