Abstract: In order to capture and aim target promptly for operators，we developed a new liner motion compensation (LMC) algorithm for EO system of aeroplane including helicopter and unmanned aerial vehicle (UAV).By recounting the velocity vector of ground target in initial east-north-up (ENU) coordinates，the angular velocity of ground target relative to EO system in inertial coordinates can be obtained, the servo software then used the value to compensate.This method could drive the line of sight (LOS) of EO system to focus on the ground target area automatically while the operator does not operate the turret in systems manual mode.This method has been validated by a UAVs flying experiment.The result indicates that in the narrow field of view (NFOV，0.70.5) of TV camera，the opening angle between ground target point and LOS point to the UAV point is all less than 1/6 FOV of the observing camera in azimuth and elevation direction.