The invention relates to the technical field of pharmaceutical packaging supplies, and particularly discloses a bottle cap high-efficiency assembly mechanism comprising a bracket, an insertion and plugging mechanism and a first feeding mechanism; the first feeding mechanism comprises a first vibration component and a first tapered charging tray which is provided with a first screw conveyer track and a second screw conveyer track, and the first screw conveyer track comprises a first screw conveyer section, a second screw conveyer section, a first torsion section and a third screw conveyer section; the second screw conveyer track comprises a first screw feeding section, a second screw feeding section, a third screw feeding section and a fourth screw feeding section; and the insertion and plugging mechanism comprises a vacuum pump, a top tray, a base tray, a semicircular guide block, a regulating part, a first driving disk, a second driving disk, a conveying fluted disk, first driving parts and second driving parts. The high-efficiency assembly mechanism has the characteristics of higher automation degree and assembly efficiency, better assembly effect, product quality guarantee, lower labor cost and higher safety.