A method of detecting audio input mode applied to an electronic device is disclosed. According to how the user presses the start button of the electronic device, the audio input mode is determined to be a short-press mode or a long-press mode. The method of detecting an audio input mode includes: detecting if a pressing time of the start button is less than a threshold time; if so, determining that the audio input mode is the short-press mode; if not, detecting if an audio time of the receiving audio of the microphone exceeds an audio threshold time during the pressing time; if so, determining that the audio input mode is the long-press mode; if not, determining that the audio input mode is the short-press mode.