Provided are a power carrier signal coupling circuit and a communication system. The power carrier signal coupling circuit includes a first power carrier signal coupling channel and a second power carrier signal coupling channel. A phase of a three-phase alternating current (AC) power line serves as a common channel, the first power carrier signal coupling channel is arranged between the common channel and one of two phases of the three-phase AC power line other than the phase of the three-phase AC power line serving as the common channel; and the second power carrier signal coupling channel is arranged between the common channel and the other of the two phases of the three-phase AC power line other than the phase of the three-phase AC power line serving as the common channel.