Frogmen formation voice communication has become a mega trend nowadays. Among various methods of modulation, single side band (SSB) multi-user voice communication system holds the advantages of remaining speakers’ tones, however with no ability of resisting interference from other users in the same frequency band. Considering the frequency band utilization of the system, there is a need for an underwater voice communication system with many frogmen working in the same frequency band simultaneously. In this work, a multi-user voice communication technology based on fast independent component analysis (Fast ICA) is proposed, which is applied to noise-free cases as well as the environment with noise. For simulation, it is demonstrated that non-noise algorithm can almost recover sources with similarity coefficient approaching 1.0 and the improved algorithm for noisy cases is able to lessen distortion and reduce interference effectively. In the experimental scenario, the average similarity coefficient between sources and separated voices can reach above 0.88 in two-user and three-user systems, which indicates that the proposed voice communication technology is able to realize multi-user transmission in the same frequency band.