Abstract: The twin-line array and line array with hydrophone triplets have been applied to removing the port/starboard ambiguity.Each of them can work well in most conditions,but not always so in conditions of targets'bearings close each other.Several typical cases are analyzed and a new bearing continuity method is proposed to improve the performance of port/starboard discrimination in this paper.The validity is verified by simulation results,and the sea-trial data acquired from line array with hydrophone triplets is analyzed to show the robustness of the method.It's expected that this method can be used for towed line array sonar.