An embodiment of the invention discloses a double-T-shaped corrugated steel web-profiled steel sheet composite beam and a construction method thereof and aims to solve the problems that an existing corrugated steel web-concrete composite beam is high in construction difficulty, and a top-flange concrete plate easily cracks under positive bending moment. The composite beam comprises a first corrugated steel web and a second corrugated steel web. A transverse connecting beam is fixedly connected between the first corrugated steel web and the second corrugated steel web. A profiled steel sheet is fixedly connected between the first top flange of the first corrugated steel web and the second top flange of the second corrugated steel web. Reinforcing steel bars or first reinforcing steel bar meshes are laid on the profiled steel sheet. A first concrete layer is pre-poured onto the profiled steel sheet with the reinforcing steel bars or first reinforcing steel bar meshes. The composite beam is applicable road bridges and city viaducts.