Abstract: In order to improve the anti-interference ability and stability of underwater acoustic speech communication and overcome the interruption and delay caused by digital transmission error codes in narrowband channel, the Fourier transform spread-compression spectrum modulation technique (FSCT) is used to transmit speech signals through ultrasonic frequency spreading, simulation channel transmission, and frequency compression restoration processing. By using the ultrasonic simulation signal with a certain bandwidth to transmit speech, the interferences of ocean background noise and multipath effects on digital communication can be avoided, and the real-time underwater acoustic communication can be achieved. The experimental results show that this method has a strong ability to resist multipath interference and can effectively improve the communication quality of underwater acoustic communication. th interference and can effectively improve the communication quality of underwater acoustic communication.