A method for controlling a motor comprises steps of: first, determining whether a switch of a motor control circuit in an electronic system is in a first state; then, operating the motor at a fanless operation mode when a temperature inside an enclosure of the electronic system is higher than zero and lower than a first threshold temperature, wherein the rotation speed of the motor is zero rpm; operating the motor at a silent operation mode when the temperature is higher than the first threshold temperature and lower than a second threshold temperature, wherein the rotation speed of the motor is a constant rotation speed; and operating the motor at a cooling operation mode when the temperature is higher than the second threshold temperature, wherein the rotation speed of the motor is a function of the temperature and varies between the constant rotation speed and a maximum rotation speed.