Abstract: Underwater channel is a multipath,complex fading channel,which badly affects the data-rate and the performance of underwater acoustic communication.Anti-multipath is an important measure to improve the performance of underwater acoustic communication.A new modulation method– SSC(Sweep-Spread Carrier) is studied in this paper.Through the simulation with actual data of underwater acoustic channel,the anti-multipath performance of SSC is investigated and the anti-multipath algorithm simplified.The basic idea of SSC is that the continuously variable frequency of the carrier is used to change the time-delay caused by multipath channel into frequency interval,and so the multipath-signals are separated in frequency domain,which well overcomes the intersymbol interference(ISI).The ef-fects of the different multipath channels and the different parameters of SSC for a given channel on the performances of SSC are analyzed.Simulation results confirm that the SSC modulation method has a good performance of an-ti-multipath for appropriately selected parameters.