The invention discloses an assembly type steel-concrete combined beam column joint structure and an implementation method thereof. The assembly type steel-concrete combined beam column joint structure comprises concrete structures, a steel structure and steel-concrete combined sections. Each concrete structure comprises concrete and steel bars. The steel structure comprises short steel beams, short steel columns, reinforced ribs and connectors. Each steel-concrete combined section comprises concrete, steel bars, reinforced ribs, shear keys, prestress cables, anchor systems, an upper steel flange plate I, an upper steel flange plate II and a lateral steel end plate, wherein the shear keys are evenly and symmetrically welded to the inner side surface defined by the upper steel flange plate I, the upper steel flange plate II and the lateral steel end plate. The prestress cables are linearly arranged in the concrete structures and the steel-concrete combined sections. The short steel beams and the short steel columns of the steel structure are connected through bolts or in a welding mode, and the steel structure is wrapped with a concrete protective layer. According to the assembly type steel-concrete combined beam column joint structure and the implementation method thereof, the use amount of steel, and the anti-corrosion, fire protection and later-period maintenance cost are reduced, the problem of wet joints in construction of a prefabricated assembly concrete structure is solved, and the construction efficiency is improved.