Abstract: Aimed at the problem that the high-accuracy localization region of the passive underwater acoustic localization system with a two vector sensor bouy is small, the redundant survey array with more buoys is adopted to achieve high accuracy. Furthermore, the influence of redundancy on the accuracy is studied. Firstly, the theory and operation steps of the multi-array localization algorithm based on bearings-only passive localization are presented. Then, the accuracies of passive localization system with various redundancies (six to twelve buoys) and array shapes are simulated. It is shown from the simulation results that the symmetrical localization error distribution relates to measuring error of direction, position of target, number of sensors and shape of the survey array. The combination of perimeter buoys results in high localization accuracy in the center of array, and the diagonal combination counteracts the low accuracy in the connection regions. Simulation results are verified in the sea trial.