For layout space in the limited land resources and improving the utilization efficiency of urban transportation bridge and traffic conditions, in this paper, according to the request of four lanes of roof, two-way urban light rail traffic in the box, considering the requirements of pipeline layout, water supply and drainage, and fire escape, lighting, ventilated at the same time, based on the existing related specification, give full play to the characteristics of the concrete box girder, preliminarily design out of the single box three rooms inclined web box girder for double-deck traffic of urban bridge, in order to provide the reference design.