Data communication method of audio interface of mobile intelligent device

The invention discloses a data communication method of an audio interface of a mobile intelligent device. A payment device is connected with the audio interface of the mobile intelligent device, and a double modulation communication mode which is formed by a combination of an FSK and an ASK is used to realize communication of the payment device and the mobile intelligent device; the ASK mode is used in an uplink, and the FSK mode is used in a downlink; and the uplink refers to transmission from the payment device to the mobile intelligent device, and the downlink refers to the transmission from the mobile intelligent device to the payment device. The data communication method of the audio interface of the mobile intelligent device is easy in implementation, and highly reliable in communication.