Abstract: To deal with the limitation of real-time sensor management algorithms, a static pre-assignment scheme is proposed based on analysis of the essential characteristics of sensor management. Afterwards, a sensor pre-assignment method based on modified particle swarm optimization is proposed, under the background of continual object tracking in low-earth orbit constellation.The simulation implemented show that the realtime computation efficiency of the proposed method is much higher than that of the realtime sensor management method, although it needs long-time static pre-assignment. As a result, the proposed method will leave more residual time for the top system.