A pneumatic metal-work tool includes a punch assembly mounted on the front end of a hydraulic push-rod assembly. The hydraulic push-rod assembly has a hydraulic chamber mounted with a piston rod. One end of the piston rod is mounted in a center hole of a piston. When the control valve of the metal-work tool has a high pressure air entered the casing to drive the piston to move, the pressure air will be converted into a hydraulic force via the hydraulic chamber so as to have the hydraulic push rod provide a punch force, and to have a metal sheet in the opening of the punch assembly punched with a hole.