In the application of passive towed linear array sonar in deep sea environment, aiming at the problem of false target discrimination in the non-end-fire direction of tugboat noise, a method for identifying the false target of seabed reflection of deep-sea tugboat noise is proposed. Firstly, based on the ray theory model, the process mechanism of the deep-sea tug noise reflected by the seabed to form a false target is given. Then, the interference characteristics of beam output power of each target at different frequencies are extracted. Finally, according to the interference characteristics, the frequency intervals of each target interference structure are analyzed to realize the false target discrimination. The analysis results of simulation data and sea trial data show that the accuracy of the false target decision is more than 95% when the interference structure is stable and the energy ratio of the reflected sound energy to the background noise energy in the beam domain is more than 8 dB. It effectively solves the problem of false target discrimination formed by tugboat noise in non-end-fire direction, providing a reference for subsequent target judgment.