A cooling system for use in a portable communication device includes a detection module, a cooling module and a central control module. The detection module detects whether the portable communication device is in a communication state and generates an acknowledgement signal. The cooling module includes a fan and a driving unit. The central control module is electrically coupled to the detection module and the driving unit, detects an operational temperature of said device, and generates a detected temperature value corresponding to the detected operational temperature. The central control module controls the fan to operate in a silent mode or a cooling mode. The central control module controls the fan to operate in the silent mode if the central control module receives the acknowledgement signal when the detected temperature value is smaller than a temperature threshold value, else the central control module controls the fan to operate in the cooling mode.