Abstract: Aiming at the problem that it is difficult to accurately model and suppress the towed array flow noise caused by the pressure fluctuation in the turbulent boundary layer, this paper analyzes the generation mechanism of the towed array flow noise and the statistical properties of the noise. A hybrid Gaussian model modelling method is developed for the non-Gaussian distributed towed array flow noise, and a low-rank model of the acoustic source signal in the multi-channel towed array is established. The parameters in the model of the flow noise and the acoustic source signal are solved by the expectation-maximization algorithm, which ultimately realizes the separation of the flow noise and acoustic source signal in the received signal of the hydrophone. The results of the flow noise suppression and target orientation estimation of the actual lake test data show that the maximum side-valve level suppression reaches 8−10 dB without affecting the localization results.