A new tracking algorithm of near space hypersonic target is proposed aimed at the problem that the multiple model algorithms are prone to choose only one single type of models in the process of adaptive conversion based on the degree of model matching. In four nonactivated filter period of different models, detections of model matching between realtime model set and real motion model are used to decide whether to activate different classes of models. By so doing, the algorithm effectively solves not only the defects in the model transformation but also the decreasing robustness of the algorithm caused by the judgment in single filter period. The simulation results show that the improved algorithm can effectively improve the tracking performance compared with the traditional algorithm.