Fabricated composite beam construction method

The invention discloses a fabricated composite beam construction method, and relates to the technical field of building construction. Comprising the steps that firstly, a prefabricated concrete bridge deck is manufactured, and concave-convex shear force grooves, grouting holes and grout emitting holes are formed in haunched positions of the prefabricated concrete bridge deck; 2, machining and assembling the steel beam, and welding group nail connecting pieces on the upper flange of the steel beam; thirdly, the prefabricated concrete bridge deck is installed, long welding studs are arranged in the grouting holes and the grout emitting holes in a sleeved mode, and short welding studs are placed in convex key teeth of the concave-convex shear grooves; fourthly, concave-convex shear grooves are filled; and fifthly, transverse and longitudinal wet joints between the prefabricated concrete bridge deck slabs are poured, and after the cement-based filler in the concave-convex shear grooves is preliminarily hardened,