Abstract: The present invention relates to a single-channel communication encoding method and decoding method, an encoding circuit, and a decoding circuit. The single-channel communication encoding method comprises: synthesizing a clock signal and a data signal into a long-short code signal, wherein the long-short code signal comprises a long code signal and a short code signal, the pulse width of the long code signal is consistent with that of the clock signal, the pulse width of the short code signal is consistent with that of the clock signal, and the duty ratio of the long code signal and the short code signal is different. According to the present encoding method, the clock signal and the data signal are encoded at the same time, the complexity of the circuit can be reduced, and packaging and wiring of a chip can be reduced.