The invention discloses a circuit structure of a carrier signal attenuator of an alternating current circuit. The circuit structure comprises an alternating current front end carrier coupling network. The input end of the alternating current front end carrier coupling network is connected with a power supply of alternating current 220V. The alternating current front end carrier coupling network is connected with the input end of a carrier impedance matching network. The output end of the carrier impedance matching network is connected with a carrier sensing interface load. According to the circuit structure, the technical problems that in the prior art, when emulation and verification are carried out on a power line carrier in a laboratory, a concentrator and ammeters are directly connected, a test environment is established by increasing the number of the ammeters and increasing the winding length of the cable of 220V, the relay depth is difficult to reach a third level, the advantage and disadvantage of a set of carrier routing networking algorithm are difficult to estimate, the attenuator produced by using the carrier signal attenuator design based on a main line cannot be used in the alternating current circuit, and therefore, simulation and emulation are difficult to carry out on a carrier networking system in the laboratory are solved.