In order to improve the tracking accuracy of active radar/infrared detector for boost-glide aircraft and give full play to the advantages of various types of observation information，a heterogeneous information fusion tracking algorithm based on multi-scale model is proposed.Aiming at the problem of different sampling frequencies of infrared detectors and active radars，a multi-scale model is constructed for the detection system.In the fast-scale model，according to the observation data of the infrared detector，the Unscented Kalman Filter(UKF) is used to complete preliminary estimation of the target state.In the slow-scale model，accurate estimation of the target state is completed by using the fused active radar observation data and the Converted Measurement Kalman Filter (CMKF).Simulation results show that the proposed algorithm can achieve more accurate tracking effect than the traditional algorithm.