Abstract: In this paper we proposed a new OFDM frequency synchronization method by using PN sequence. In multi-path channel, the frequency estimation precision of this method is better than conventional method for it using multi-path signals. The simulation indicates the proposed method can satisfy the demand of OFDM system at moderate moving rate in Rayleigh channel. One of the advantages of this method is that its frequency estimation range can be dozens of subcarrier spacing when the parameters are properly designed. And the frequency estimation range and precision can be adjusted.