Abstract: In the case of the underground space communication interruption after the occurrence of the sudden disaster, the emergency acoustic communication system based on the rigid pipelines can provide effective communication for underground trapped persons. In the existing pipeline emergency acoustic communication system, there is a disadvantage of low transmission efficiency. Aiming at this problem, a method of pipeline emergency acoustic communication based on differential pattern and time delay difference coding was put forward in this paper, which can effectively improve the transmission efficiency of the pipeline emergency acoustic communication system. The actual pipeline experimental results proved the effectiveness and feasibility of the method, and compared with the original system, its communication rate was improved greatly under the same conditions, and it has certain anti-interference performance.