A device for detecting an audio interface includes a processing unit, a first audio interface transmitting circuit, and a second audio interface transmitting circuit. The processing unit is utilized to generate a clock signal and a word select (WS) signal. The first audio interface transmitting circuit is utilized to generate a first audio data according to the clock signal. The second audio interface transmitting circuit is utilized to generate a second audio data according to the clock signal and the WS signal. The processing unit switches to the first audio interface transmitting circuit if a voltage potential of the WS signal remains at a high voltage level or remains at a low voltage level longer than a predetermined period. The processing unit switches to the second audio interface transmitting circuit if the voltage potential of the WS signal changes during the predetermined period.