Plant image extraction is the basis for determining the plant location, which is in the field of image segmentation. The image color information cannot be ignored on one hand, based on this point of view, a colored region segmentation method is proposed. Because of the large green component of the plant, it is possible to use the maximum component extraction method to realize the segmentation of the plant in the image. The method has minimum calculation and operates only on pixels. In addition, the method can not only separate the buildings and plants, but also make the image more accurate. Adaptive threshold binaryzation calculation method can be used at real time according to the brightness of the image and can be better adapted to image binaryzation processing at different light condition. The examples prove that the method is effective and reasonable.