An adaptive method and device of an audio interface and an electronic signature token are provided. The audio interface comprises a first pin and a second pin, and the method comprises: not implementing an identification operation on the first pin and the second pin of the audio interface when an absolute value of a voltage difference between the first pin and the second pin is less than a first threshold; determining a type of each of the first pin and the second pin according to a sign of the voltage difference between the first pin and the second pin when the absolute value of the voltage difference is greater than or equal to a second threshold, in which the second threshold is greater than or equal to the first threshold; and connecting the identified ground pin to a common ground.