Abstract: In the long-distance propagation of deep-sea acoustic pulse signal, due to the propagation loss and the impact of background noise, the received signal-to-noise ratio 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 muti-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 was given, and the calculation model of multi-pulse signal joint detection probability and false alarm probability was derived. The detection performance of the proposed method was verified by calculating the receiver operating characteristic under different signal to noise ratio conditions, and the traditional single-echo Power-Law detection method was compared. 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 improved than that of single echo Power-Law detection. The research results provide theoretical basis and technical support for long-distance high-probability detection of deep-sea target pulse signals.