In order to promote the construction of the large span simple supported steel-concrete composite girder bridge，the design and construction scheme were investigated for proposing the force calculation method of steel-concrete composite beams based on the 73m single span simple supported steel-concrete composite girder bridge in Hong De North Road Project in Foshan. The results show that live load composite girder is not suitable for the large-span simple supported steel-concrete composite girder bridge. According to the situation of the bridge bottom，the number of temporary supports should be set up as little as possible to reduce the temporary measures cost and the impact on the existing structures. Furthermore，when the concept of assemblage is introduced into the design and construction of composite beams，which is advantageous for construction quality control and rapid construction.