To the problem that how to select the most suitable member for the leader of social capital consortium of expressway build-operate-transfer(BOT) project, based on the methods of literature analysis and expert consultation, the index system and the group-extensible model of member selection and evaluation were established for the leader of social capital consortium of expressway BOT project. The effectiveness of the index system and consortium member selection model was indicated by a practical application.The results show that the leader selects the member of social capital consortium according to the cooperation needs, and the evaluation index may include working ability of financing, construction, management, operation and maintenance, etc. The group-extensible model can be used to select and evaluate member of social capital consortium, and it is scientific and effective.