Power line communication system for pursuing variable channel environment according to variance of load

A power line communication system for tracking a variable channel environment in accordance with changes of a load is provided to apply a decision making algorithm according to various power line channel environments, thereby adaptively selecting and transmitting only optimum modulation/demodulation methods suitable for each power line channel environment. A power line communication system for tracking variable channel environment in accordance with changes of a load comprises the followings: a power line detector(220) which detects the voltage signal and current signal of a load device(210) connected to a power line; a power line diagnosing unit(230) for diagnosing a channel state of the power line from the voltage signal and the current signal of the load device(210); a lookup table(240) for storing information about optimum modulation/demodulation methods and protocols according to each load-changed channel; and a communication method selector(250) which selects the optimum modulation/demodulation methods and protocols from the lookup table(240) according to a channel state of the power line inputted in the power line diagnosing unit(230).