The angle tracking loop in airborne radar facing to a maneuvering target plays a vital role in the joint 3D-tracking of range, velocity and angle. This paper analyses the disadvantage of the conventional Kalman filter algorithm employed to track a maneuvering target’s angle, which are a low tracking precision and a slow convergence rate of angle tracking error. In order to solve these problems, a novel angle tracking algorithm called Bend Degree Tracking Loop Filter (BDTLF) is put forward to detect the corners in target’s angle curve by bend degree detection and adjust the loop noise bandwidth adaptively to control angle tracking loop. The proposed algorithm accelerates the convergence rate in angle tracking loop, lightens the filtering disturbance around target’s angle curve corners, and keeps the continuity of filtering performance. The computer simulation results demonstrate that compared with the angle tracking loop using Kalman filtering algorithm, particle filtering algorithm, α-β-γ filtering algorithm or a constant coefficient loop filter, this novel method has a more satisfying performance in angle tracking of weakly maneuvering targets.