Differential time delay shift coding can effectively suppress the interference of multipath channel, so it is widely used in underwater acoustic communication to realize the reliable transmission of information. In this paper, an underwater acoustic emission system based on differential delay difference coding is designed. According to the characteristics and requirements of differential time delay shift coding, the symbol is generated by waveform storage direct reading, which is transmitted and stored in the memory. Then the system is configured with communication coding parameters. Finally, the communication information is encoded through the differential time delay shift coding and transmitted by the digital-to-analog converter and low-pass filter and transducer. Lake communicaton experiment shows that the acoustic emission system can ensure the accuracy of the coded information and the reliability of the transmitted information under different parameters. So this system has certain practicality.