As a new type of construction financing mode， the“PPP+EPC”avoids the short-age of design， construction divorcing from operation of PPP infrastructure projects and the excessive leverage of social capital.Under this mode， the choice of the general contractor by the government department will often determine the successor failure of the project.Com-bining the characteristics of PPP and EPC mode， general contractors selection index system and optimum decision model using discrete Z-number utility theory which considers the un-certainty of subject in the evaluation process a represented.Finally， the rationality andpracticability of the model are proved by sorting and selecting the evaluation object with an example， and a new method and idea for selecting the general contractor are provided.