The invention relates to a cable well top plate structure and construction, in particular to a superposed type cable well top plate structure and a construction method thereof. The superposed type cable well top plate structure is characterized in that H-shaped steel main beams, channel steel secondary beams, steel plates and pouring concrete slabs are included; the two ends of each H-shaped steelmain beam are erected on L-shaped steps on the tops of the two side walls of a cable well, the channel steel secondary beams are located on the lower end faces of upper flanges of the H-shaped steelmain beams, the two ends of each channel steel secondary beam and the two adjacent H-shaped steel main beams are welded, the channel steel secondary beams are fully paved with the steel plates, and the steel plates are parallel to the H-shaped steel main beams; and anti-shear steel members are welded to the upper end faces of the upper flanges of the H-shaped steel main beams, the concrete slabs are poured on the H-shaped steel main beams and are fully paved with the steel plates, and the H-shaped steel main beams are connected to the cast-in-place concrete slabs through the anti-shear steel members. The cable well top plate structure and the construction method have the advantages that construction is facilitated, no scaffold needs to be erected in the construction process, the construction period can be effectively shortened, the construction efficiency is greatly improved, and the waterproof performance is ensured. In addition, a steel support frame is fully used, and the stress performance of the top plate is improved.