The invention belongs to the field of heat treatment and relates to 0 DEG C cold quenching equipment. The 0 DEG C cold quenching equipment carries out quenching by adopting the mode of mixing water with liquid nitrogen and is divided into three systems: a closed cold quenching tank system formed by a cold quenching tank (3), a cold quenching tank cover (1) and a water inlet pipeline (2), a liquid nitrogen supply and nitrogen recovery system formed by a nitrogen emptying pipeline (9), a nitrogen recovery gas bag (10), a nitrogen recovery pipeline (11), a liquid nitrogen container (12) and a liquid nitrogen delivery pipeline (13), and a piston mechanism formed by a workpiece handling piston (4), a piston rod (14), a hydraulic cylinder (8) and a rubber seal ring (5) and used for stably sending and fetching heat treatment workpieces. The 0 DEG C cold quenching equipment has the advantages of safety and convenience in operation, accurate and constant quenching temperature, small usage amount of liquid nitrogen, reutilization of nitrogen, no pollution, and the like.