In order to solve the problem that it is difficult for the telemetry antenna to continue to track in real time under the abnormal flight of rocket, this paper proposes a prediction method for the real-time tracking angle after the abnormal flight of rocket. In this paper, several common coordinate systems and their transformation relations are introduced firstly. The motion of rocket after abnormal flight is simplified to the free fall motion, considering the inertial velocity. The free fall velocity model and the calculation method of real-time tracking angle are given in this paper. Simulation experiments are designed to verify the effectiveness of the proposed method.