The upper surface of the polar sea area is covered with a large amount of sea ice throughout the year, with weak solar radiation influence. Sound speed profile exhibits a positive gradient with depth, while high-frequency sound waves are easily scattered when propagating under the ice, causing multi-path interference and reverberation interference. These phenomena contribute to the complexity of the working environment of multi-beam sonar in the polar sea area. None of the existing technologies can accurately simulate sonar echo signal in the polar environment. Therefore, it is urgent to develop a sonar echo signal model that can effectively simulate the acoustic field characteristics in polar regions. In this paper, an echo signal simulation model of multi-beam sounding sonar in polar regions is constructed by considering ship noise, multi-path effects and sea surface reverberation. In the low-latitude sea environment, the simulated signals generated by the model are consistent with the signals received by a real ship on the waveform trend, which verifies a high reliability of the model. This model can ensure the effective evaluation of polar multi-beam sounding sonar system, and support the verification of polar terrain navigation algorithms.