The invention provides a power line carrier wave meter based on tri-state impulse displacement phase modulation and a communication method. The power line carrier wave meter consists of at least one of a multifunctional special integrated circuit or a CPU or an MCU or a DSP data processing controller, a PLC communication circuit, an electric energy metering circuit, a display circuit and a power circuit. The communication modulation demodulation of the PLC communication circuit adopts the tri-state impulse displacement phase modulation demodulation. The PLC communication circuit, an A/D and D/A switching integrated circuit (IC) and a digital filter are formed into a PLC two-way communication circuit; and the PLC two-way communication circuit is coupled to a power line network through a coupling component to perform the two-way communication with a master station. As the carrier wave modulation demodulation of the PLC carrier wave electric energy meter adopts the tri-state impulse displacement phase modulation demodulation, and a signal which is transmitted on a link only corresponds to an impulse displacement phase and is irrelevant to the size of the signal, the invention improves the performances of attenuation resistance and interference resistance, and greatly improves the reliability and the success rate of the carrier wave communication of the electric energy meter.