Considering the various errors existed in the data from ADS-B surveillance system and the flight characteristics of low-altitude aircraft, a new algorithm for track monitoring based on ADS-B was proposed.The decision threshold was set up to achieve multi-mode switching for aircraft.The advantage of Kalman algorithm was exploited in the steady phase and the smooth and stable performance of RMIMM was used in the maneuvering phase.Comprehensive performance of the algorithm is superior to that of the conventional monitoring algorithm based on Kalman filtering.The shortcoming that the response of Kalman filter is inadequate when processing the high frequency signal is overcome while the good tracking performance of it when processing the low frequency signal is kept.Besides, the multi-mode switching based on different modes is achieved, and the future mode can be predicted rapidly.