The orthogonal frequency division multiplexing（OFDM)， technology combining with frequency hopping(FH) technology will increase system capacity, improve transmission rate, and effectively resist multi-path fading and interference. Therefore, FH-OFDM technology is applicable in high speed communication of the power line. Based on the characteristics analysis of low voltage power line channel, the design scheme of a FH-OFDM system is presented. The system is simulated by MATLAB. It is shown that the bit error rate(BER) performance of the FH-OFDM system is better than that of the traditional OFDM and FH system.