A vibration reduction device upon KEY-OFF of an engine may include a fuel injection device for injecting fuel stored in a fuel tank into a combustion chamber of an engine depending upon a target torque value, a measurement device for measuring the RPM and the rotational torque of the engine, and an controller for detecting whether or not an engine becomes KEY-OFF and when it is determined to be in KEY-OFF state, setting a reference torque value, and setting a torque value changing the reference torque value depending upon a predetermined reference as the target torque value and controlling the fuel injection device to finely inject fuel into the engine depending upon the target torque, thus reducing engine vibration.