A cooling system for a projector is provided and disposed in the projector. When a sensing temperature of the projector sensed by a thermal sensor of the cooling system is higher than a maximum temperature, a control module controls a fan to increase a rotation speed. When the sensing temperature of the projector sensed by the thermal sensor is lower than a minimum temperature, the control module controls the fan to decrease the rotation speed. As a result, the temperature of the projector is maintained within a proper range.