The invention discloses an AC power line carrier communication system which comprises a plurality of communication nodes, wherein each communication node comprises a single-chip microcomputer, a poweramplification circuit, a zero-crossing detection circuit and a signal coupling circuit. In each communication node, the single-chip microcomputer is connected with an upper computer and is used for modulating a data signal into a modulation signal and then sending the modulation signal to the power amplification circuit; the power amplification circuit is used for carrying out power amplificationof the received modulation signal; the zero-crossing detection circuit is used for detecting a zero-crossing signal of an alternating-current signal in an electric power circuit; and the signal coupling circuit is controlled to couple the output signal of the power amplification circuit to an electric power circuit at the moment of the periodic zero-crossing signal, wherein the time period of thesignal coupling circuit in the data coupling transmission process is 1 millisecond. The system reduces the pulse impact of the peak signal of the electric power signal on the data signal.