Considering the problem of trajectory prediction of low-altitude free flight targets,a new method was proposed from both strategic and tactical considerations.Based on TC report from surveillance data by ADS-B,multi-parameter offset value of target were taken into consideration,and the fading memory and moving window smoothing model were introduced into comprehensive historical information.The flight intent inference was achieved,which was suitable for low-altitude flight,then the trajectory by strategic prediction was obtained.A trajectory prediction idea based on both tactical prediction and strategic prediction was also proposed according to a new algorithm for tracking and monitoring,which can be used for predict the medium and long term future trajectory of a target.