Abstract: Multi-Carrier Code Division Multiple Access(MC-CDMA) is a combination of Orthogonal Frequency Division Multiplexing(OFDM) and Code Division Multiple Access(CDMA), and has their both advantages.In under-water acoustic communication, there is serious multipath interference, marine environment noise, and space-time varying properties, which make the underwater acoustic signals attenuated greatly.MC-CDMA is used in underwater acoustic communication for its high-speed data transmission and reliable performance.In the paper the basic principle of MC-CDMA is analyzed, and it is tested that MC-CDMA has better performance in underwater acoustic communi-cation than OFDM via the simulation for MC-CDMA and OFDM and the experiment in pool.