Power line carrier communication method and power line carrier communication system

The invention relates to a power line carrier communication method and a power line carrier communication system. The method is applied to slave equipment, and specifically comprises the following steps: acquiring a main carrier signal input to a bus from main equipment so as to take electricity from the main carrier signal, and decoding the main carrier signal so as to acquire main equipment transmission information; wherein the main carrier signal is configured to be a square wave signal, and the high level duration time and/or the low level duration time of each pulse period in the square wave signal are/is set based on the transmission information of the main device; modulating a subcarrier signal capable of transmitting the transmission information of the slave equipment according to the transmission information of the slave equipment; and monitoring the level change of the main carrier signal so as to input the subcarrier signal to the bus within the low level duration of the main carrier signal, so tha