A Morse code input method and a portable electronic device for performing the method are provided. The portable electronic device includes a processing circuit and a touchscreen. The method includes: sensing touch events by the touchscreen, recording and comparing time periods of the touch events by the processing circuit; identifying, by the processing circuit, inputs in the ith touch event through (k−1)th touch event as short signals when the time period of the kth touch event is greater than or equal to N times the time period of (k−1)th touch event and the kth touch event is not the last touch event, wherein N is a positive number, k and i are positive integers, with k being greater than or equal to i, and the ith touch event is the earliest one of the touch events in which inputs have not yet been identified as long or short signals.