With the continuous development and popularization of UAV remote sensing technology, its application in ecology and other fields has become a research hotspot. Vegetation coverage information extraction is one of the important application fields of UAV remote sensing. However, there are some problems in vegetation coverage extraction of UAV image, such as difficult to select the threshold, long time consuming and so on. In this paper, a method based on HSV color space and Otsu is proposed to improve the speed of image segmentation. This method transforms the color space of UAV image from RGB to HSV, extracts H component from HSV color space, and combines Otsu threshold segmentation method to extract vegetation coverage quickly and automatically. The experimental results show that Otsu algorithm can significantly shorten the extraction time of vegetation coverage, and the extraction accuracy is higher, and the accuracy is higher when combined with HSV color space. Compared with traditional vegetation coverage threshold extraction, Otsu algorithm has obvious advantages, and improves the speed and accuracy of vegetation coverage extraction. It provides a new method for the extraction of vegetation coverage.