To estimate the movement of micro unmanned aerial vehicle (UAV) independently and accurately, a new method for estimating the micro UAV states of motion is presented in this paper using a micro inertial measurement unit (MIMU) combined with a stereo camera pair.The movement of a micro UAV is deduced using the measurements of the MIMU while two sequences of images are taken by the stereo camera pair, from which several feature points are extracted and matched.The movement of the micro UAV and the position of these feature points are estimated by measuring the position of these feature points in sequence images.This approach is realized via a Kalman filer.Finally, a simulation is performed by assuming a micro UAV flying at a height of 50 m with a stereo camera pair whose image resolution is 800 pixel×600 pixel and whose baseline is 0.6 m.For the feature points about 150 m away, the error percentage of distance estimation is around 3% using the method proposed in this paper, and the error of velocity estimation is about 1 m/s.The results of the simulation demonstrate that the method in this paper is efficient even in a comparatively large field of environment.