A dead time compensation method for reducing the vibration of a speed variable device of a tread mill applied induction motor is provided to improve operation performance by reducing vibration and noise in a low speed operation below 2Hz. A dead time compensation method for reducing the vibration of a speed variable device of a tread mill applied induction motor includes the steps of: converting DC current outputted from an inverter to a synchronized frame of a coordinate system; filtering the converted DC current by passing the converted DC current through a low pass filter; and converting the filtered DC current to a rest frame of the coordinate system again for compensating the dead time.
