The invention discloses a connection construction process for a composite beam with an assembled welding stud connector. The connection construction process for the composite beam with the assembled welding stud connector comprises the following steps of 1, making a steel beam, and welding a base of a welding stud connector on the steel beam; 2, transporting and mounting the steel beam with the welded base to a designated bridge position; 3, hoisting a precast concrete bridge deck slab to the steel beam so that a reserved hole in concrete corresponds to the position of the base of the weldingstud connector; 4, screwing a threaded rod part of each welding stud connector to the base of the welding stud connector; 5, filling a cement-based material into the reserved hole of the concrete bridge deck slab; and 6, curing the cement-based material in the hole till a designed strength requirement is satisfied. According to the connection construction process for the composite beam with the assembled welding stud connector, the defect of a traditional welding stud connector in the concrete bridge deck slab construction can be effectively eliminated, the construction efficiency can be enhanced, and the bearing capacity of the welding stud connector can be improved.