Abstract: The complexity of power line channel makes the task of improving communication quality difficult. Orthogonal Frequency Division Multiplexing (OFDM) could make a full use of frequency bandwidth and improve the capability of anti-multi-path fading and it can be implemented by Discrete Fourier Transform (DFT) by using DSP in practice. So the quality of power line communication could be improved. Characteristics of power line channel such as impedance, fading and disturbance are analyzed. These characteristics are related with considerable time-variant and frequency attenuation of signals. A simple model of low voltage power line channel is established in this paper to reflect the characteristics of power line channel approximately. An improved method is proposed in order to apply OFDM to power line carrier communication, with N subcarriers in each OFDM symbol to transfer N same codes. Theoretically, in the receiver, N codes demodulated from each OFDM symbol are the same but the error code could be induced by various disturbances. So a special operation is used in the receiver for finding the right code. The reliability of the communication is increased by sacrificing the speed, as has been simulated by establishing a Matlab model. It is indicated by the simulation result that reliable data transfers can be achieved for a bad power line channel with high error code rate. The problem of this method while being implemented on a project will be discussed in future.