Abstract: The high resolution images can be acquired by an Unmanned Aerial Vehicle (UAV) flying at low altitude. Because of air turbulence and unstable flight conditions, the motion blur amount caused by the UAV system is more complex than the manned professional aerial platforms. To meet the potential demand of high resolution remote sensing applications, both theoretical and quantitative analysis were conducted about the factors which caused image blur.It is proposed that the forward blur still occupied the leading position of the whole motion blur amount. However, the bigger attitude angles enlarged the forward motion blur amount at image edges. Moreover, the motion blur caused by the larger angular velocity within the exposing time could not be neglected. Finally, quantitative experiments on low altitude UAV remote sensing indicated the camera angles and angular motion in roll, pitch and heading direction should be controlled with quantitative values in order to decrease the motion blur of images from UAV.