A portable communication device includes a receiving module, a pulse signal generating module, a timer module, and detection module. The receiving module is configured for receiving incoming signals sent to the portable communication device. The pulse signal generating module is configured for generating pulse signals when a portable communication device body is tapped. There is a first predetermined limit and a second predetermined limit, and the timer module is configured for starting timing when the pulse signal generating module generates the pulse signals, and stopping timing at the second predetermined limit. The detection module is configured for starting to detect if the pulse signal generating module generates pulse signals at the time between the first predetermined limit and the second predetermined limit. The detection module directs the receiving module to refuse or accept the incoming signals according to detecting results.