A GFRP-RPC composite beam bridge for double deck traffic is designed. The bridge is composed of two GFRP trusses and ribbed plates, which are connected by glue bolts. The composite beam bridge is formed by pouring self compacting RPC concrete. The scale model (1:8) of composite beam bridge is tested and analyzed by quasi-static loading test and finite element method, and its elastic performance is studied. The results show that: After pouring RPC, the stiffness of the beam bridge increases about 2.6 times, which indicates that the combination of GFRP and concrete is conducive to the reasonable stress of the structure, and the deformation of the beam bridge increases about 10% when the lower part is loaded, which is unfavorable to the structure; the chord stress accords with the assumption of plane section, and the stress of composite structure is more reasonable; the upper and lover chords are in the force state of compression bending and tensile bending respectively, when the upper and lower chords are loaded, the tensile stress of the lower chords is about 1.5 and 2.5 times of that of the upper chords, and the lower chords are weak chords; when the diagonal web member is in tension, the straight web member is basically in compression state, and the loading mode of up and down affects the stress form of the straight web member. The design with larger local tensile and compressive stress should be considered for the lower bearing; the concrete on the side of the top plate is compressed, while the concrete on the side of the bottom plate is tensioned, indicating that the setting of the web member is conducive to the uniform stress of the slab concrete.