Abstract: Pulse radar serves as a crucial external measurement data source for target spacecraft. The inaccurate angle measurement information obtained during sidelobe tracking can lead to errors in orbit determination. Existing methods for radar sidelobe tracking discrimination predominantly rely on operator experience, which suffers from insufficient timeliness and accuracy. By analyzing the radiation pattern characteristics of pulse radar antennas, the mechanism of sidelobe tracking, and actual measurement data, this paper innovatively proposes a sidelobe tracking discrimination method based on the sum-difference amplitude ratio. Verified through actual mission data and UAV tracking experiments, the method can effectively identify the radar sidelobe tracking when the discrimination threshold is set to -5 dB. This algorithm features low computational complexity, high real-time performance, and high accuracy, offering valuable insights for sidelobe tracking discrimination in other measurement and control equipment.