The invention relates to a steel-RPC (Reactive Powder Concrete) composite bridge. Conventional bridges generally adopt reinforced concrete or prestressed concrete structures and are required to be cast in situ or erected in entire holes after prefabrication, and the construction expenses are high. The steel-RPC composite bridge is characterized in that two RPC longitudinal beams with beam surfaces which face to each other are longitudinally arranged, and the top of the bridge is covered by RPC bridge decks; the RPC longitudinal beams and the RPC bridge decks are longitudinally divided into multiple sections and the multiple sections are mutually spliced; a U-shaped embedded steel plate is arranged at the end part of each section of the RPC longitudinal beams; after two adjacent sections of RPC longitudinal beams are spliced, gusset plates are arranged on the two sides of the transverse direction of a longitudinal beam joint; bolts penetrate through the gusset plates on the two sides to splice and fix the two adjacent sections of RPC longitudinal beams; connecting steel boxes and connecting frame bents are arranged between the two rows of RPC longitudinal beams. The steel-RPC composite bridge has the advantages that the structure is simple, the stress is clear, the materials are novel, the mechanical property is good, the bridge can be prefabricated and transported section by section and can be spliced on the site, the tensile strength and the compressive strength of RPC are fully utilized, steel bars or prestressed bars are not necessarily configured in the structure and the durability is better.