An algorithm of tracking moving target on the ground by unmanned aeria.vehicle (UAV) based on improved correlation filter is proposed. Multiple features of thetarget, such as histogram of gradient ( HOG ) feature, color names ( CN) feature.convolutional neural network ( CNN) feature are extracted. To improve the trackingperformance of irregular objects, the spatial reliability graph is used to improve thecorrelation filter. Based on efficient convolution operator, feature dimension reduction andcompact sample space are constructed to reduce data redundancy. The position of the targettracking box is determined according to the target characteristic response obtained by thecorrelation filter. So the target tracking is accomplished. Experimental results show that themean centre location error (CLE) is 16.07, the area under curve(AUC) of tracking successrate is 0. 54. Both evaluation parameters are superior to other advanced algorithms. Thealgorithm can track small moving target accurately in real time, with an average frame rateof 44.09 frames per second.