Abstract. In this paper, we conduct research on effective and robust time-delay estimation methodology for spread spectrum communications. The development of underwater acoustic spread spectrum communication technology derived from the demand for underwater remote, reliable communication. Due to the underwater acoustic channel belt width, background noise and high rate of Doppler frequency shift, severe multipath effect, absorption problems such as uneven, makes the communication quality serious decline. We firstly analyze the fast time-delay estimators to serve as the prior knowledge, and later, we analyze the channel estimation techniques. Finally, we test the error and efficiency. Results show that the system has better ability to resist noise and multiple access interference, and improve the chaotic spread spectrum sequence to better the performance of the system of traditional chaotic spread spectrum sequence. The experimental result proves the effectiveness of proposed methodology. In the future, we plan to conduct more literature reviews to modify the current technique.