Abstract: To the problem of fish abundance inversion,a method based on broadband echo signal statistics is established.Firstly,considering the randomness of fish shoal activity in nature state,and by simplifying the echo signal waveform,the modeling of pulse-compression output signal of fish broadband echoes is realized.Then,by using the coefficients of variation of signal strength as the statistical feature quantity,the numerical relationship between the statistical feature and the fish abundance is derived.The simulation and sea experiment results show that the proposed method can effectively achieve fish abundance inversion,and it's more precise and requires fewer samples when compared with the existing narrowband inversion method.Compared with the mainstream echo-integration method of fisheries acoustics,this method does not rely on prior knowledge of fish school,and does not need to calculate the absolute acoustic quantity of the sonar signals,which shows great application prospects.