The utility model belongs to the technical field of the engineering is consolidated to public road bridge roof beam, a highway T roof beam cross slab prestressed reinforcement structure is disclosed. Its main technical characteristics does: including the roof beam body and cross slab, the horizontal bridge of cross slab is to both sides and the following concrete reinforcement body that is provided with following and that personally experience sth. Part of the body to the roof beam in the same direction as the bridge in the cross slab both sides, be provided with horizontal bar planting between the roof beam body and the concrete reinforcement body, roof beam body bottom is provided with vertical bar planting, be provided with the flat bellows of horizontal main reinforcement and built -in transverse prestress muscle in the concrete reinforcement body, horizontal main reinforcement and flat bellows are connected through big stirrup and horizontal bar planting respectively, be connected through little stirrup and vertical bar planting, concrete reinforcement body both ends are provided with the anchor lower bolster, porous flat ground tackle. This highway T roof beam cross slab prestressed reinforcement structure does not destroy the roof beam body, utilizes prestressing force initiative reinforcement technique to solve the horizontal connection disease problem of public road bridge roof beam, the utilization efficiency that improves T roof beam durability and increase the supporting material.