The invention discloses a shallow sea multi-path sound signal decomposition method. The shallow sea multi-path sound signal decomposition method includes the following steps that a sonar emitting device emits signals, and a sonar receiving device receives signals; the delay of each multi-path sound signal is extracted from the received signals; the emitted signals are delayed according to the extracted delay, and an actual source signal and N-1 virtual source signals are obtained; the obtained actual source signal and N-1 virtual source signals serve as input, the received signals serve as output, and an ARX model is constructed; the kth virtual source signal serves as input and fed into the ARX model, the other k-1 virtual source signals are set as 0, and a sound signal is obtained; it is made that k=k+1, the former step is repeated until k=N, and N sound signals are obtained. The shallow sea multi-path sound signal decomposition method effectively improves the decomposability of the multi-path signals.