Abstract: This paper describes a new underwater acoustic communication system which is performed in the multipath channel. The multi-dimensional channel coding technique which uses the signal pattern and the information source coding technique which uses the shift of signal time-delay have been combined in the signal code design. So that, the system could have high ability of anti-interference of multipath arrives, and obtain a high data ratio. In the first experiment at a reservoir, successful transmission of 200 bits/s over a 1 km horizontal path was achieved.