A short-stroke synchronizer comprises a gear hub, wherein the gear hub is sleeved with a gear sleeve, a shifting gear is arranged on each of two sides of the gear hub, a combination gear ring is arranged on each of outer walls of inner ends of the two shifting gears and is sleeved with a locking gear ring, each locking gear ring is sleeved with a synchronizing ring, the outer conical surface of each synchronizing ring is matched with the inner conical surface of the gear sleeve, spline teeth are circumferentially arranged on inner surfaces of the synchronizing rings, tooth side surfaces and locking surfaces are arranged on the spline teeth, spline tooth grooves matched with the spline teeth are arranged on outer surfaces of the locking gear rings, spline tooth groove limiting surfaces and spline tooth groove locking surfaces are sequentially arranged on side surfaces of inner ends of the spline tooth grooves from inside to outside, bosses with top surfaces being inclined surfaces are arranged on the outer surfaces of the locking gear rings and are staggered with the spline tooth grooves, limiting retaining rings are arranged in positions, corresponding to the inner sides of the synchronizing rings, of the outer surfaces of the locking gear rings, and elastic pressing rings are arranged in positions, corresponding to the outer sides of the synchronizing rings, of the outer surfaces of the locking gear rings. The short-stroke synchronizer is applicable to gearboxes.