In long-span railways, highway bridges and urban overpasses, deadweight often accounts for the majority of the total load, and steel-concrete composite bridges have great advantages. Based on the design case of Jiaxing Expressway Viaduct, this paper carries out the statistical analysis of structure, stress, materials and economy cost of the continuous and simply supported composite girder bridges on the main line and interchange ramp. Some useful conclusions are obtained and can provide reference for similar projects.