The invention discloses an application of a quick mechanism in a combined on-load tap-changer. The quick mechanism is installed in the combined on-load tap-changer and comprises a fixed plate, a triangular shaft, a driving gear, a counter shaft, a driven gear, a crank arm, a spring, a locking wheel assembly, a sleeve spindle, a grooved wheel and the like. 360-degree stepping switching of a switch switching core is achieved through control on a transition vacuum tube through a grooved wheel mechanism, a radial cam and an axial cam; and reciprocating motion switching is avoided.