Abstract: In deep-sea environment, due to the long distance propagation loss and background noise, the received signal-to-noise ratio of acoustic pulse signal is reduced, which increases the difficulty of signal detection at the receiving end. In order to improve the pulse signal detection performance of receiving equipment, considering the multi-path propagation characteristics of pulse signal under the condition of deep-sea reliable sound path, a new deep-sea multi-path pulse signal joint detection method based on Power-Law is proposed, the principle of joint detection pulse selection is given, and the calculation model of joint detection probability and false alarm probability is derived. The detection performance of the proposed method is verified by calculating the receiver operating characteristic under different signal to noise ratio conditions, and it is compared with the traditional single-echo Power-Law detection method. The results show that under the same false alarm value, when the signal to noise ratio is lower than 0 dB, the performance of multi-path Power-Law detection is significantly better than that of single echo Power-Law detection. The research results provide theoretical basis and technical support for high-probably detection of long-distance target pulse signals in deep sea.