Abstract: Kalman filtering is widely used in acoustic maneuvering target tracking. However, conventional Kalman filtering always fails to track the maneuvering target when there is a sudden change in the target movement direction. In this paper, an adaptive factor to adjust the Kalman gain is generated based on the changed movement direction of the acoustic maneuvering target. Numerical simulation and sea trial results show that the proposed adaptive Kalman filtering can not only quickly respond to the sudden change of target movement direction, but also has smaller position tracking errors in comparison with the conventional Kalman filtering, and furthermore, it has good stability and fast convergence.