Abstract: To solve the port-starboard fuzzy problem in conventional towed array sonar, a port-starboard discrimination method based on platform maneuver and target tracking is proposed. A mirror target is generated firstly, and a port-starboard target pair is formed. The port-starboard discrimination is realized by the velocity difference between the real target and its mirror target. The simulation results show that, if the target is over more than 10 km away, and whether it is on port or starboard, the velocity difference between the real target and its mirror target will be greater than 5 m·s^-1 in two scanning periods after the platform steers 5°, and so the port-starboard discrimination can be realized, moreover, the difference of azimuth variation between the two targets can be taken as an auxiliary reference. The method has a certain application prospect and guiding significance in engineering practice.