Disclosed is a method for precisely sensing an amount of laundry of a washing machine without influence of static friction. The method includes the steps of (a) operating a motor, and then carrying out regenerative braking of the motor, (b) re-operating the motor after the step (a), and then carrying out rheostatic braking of the motor, and (c) determining the amount of laundry by means of the principle of the conservation of energy in the regenerative braking of the motor in the step (a) and the principle of the conservation of energy in the rheostatic braking of the motor in the step (b).