The present disclosure relates to a data transmission method, device, system, and display device. The method includes: encoding clock training data to obtain two sets of encoded data corresponding to the clock training data and complementary to each other; and sending a specified set of encoded data in the two sets of encoded data to a receiving end when positive and negative pins of the transmitting end and the receiving end are correspondingly connected; sending other set of coded data in the two sets of coded data than the specified set of encoded data to the receiving end when the positive and negative pins of the transmitting end and the receiving end are reversely connected, the receiving end being configured to perform clock training according to the received encoded data. With the method provided by the present disclosure, when the positive and negative pins of the transmitting end and the receiving end are reversely connected, the receiving end may also correctly receive and decode data, thereby effectively improving the reliability and flexibility of data transmission.