Abstract: To solve the problem of the Orthogonal Frequency Division Multiplexing (OFDM) inter-symbol interference caused by underwater acoustic multipath channels, a passive time reversal channel equalization scheme is proposed. Time reverse the probe signal and convolute it with the OFDM signals. The inter-symbol interference caused by multipath channels will be alleviated on the time focusing principle of passive time reversal mirror. There is no need for pilots to realize the channel equalization which simplifies the processing steps and enhances the bandwidth efficiency. The bit error rate performances are compared to the least square channel equalization. The simulation and lake experiments results show that the passive time reversal channel equalization can alleviate the influence on the OFDM underwater acoustic communication caused by the multipath channel effectively.