This application is skillful to diagnosis the Dendrobium disease by leaf images. First, Yellow leaf spot is a common disease of Dendrobium and it causes significant yield loss. The disease is often observed on the leaves. The first symptoms appear on leaves as small yellow oval spots. Lesions may expand to one centimeter in diameter, and are surrounded by a yellow margin with black powder inside. Individual lesions may vary in shape and size, often expanding and joining together with other lesions. Second, Black spot is various sizes and develops on leaves. The figure is quite round and be surrounded by black margin. The centre of spot is dried, and sank from normal tissue. Third, Anthracnose disease infects by the air and the leaves are most often attacked. It changed brown beginning at the apex and proceeding toward the base. Dark brown is expands across direction of the leaf. The affected area is usually sharply defined, while the remainder of the leaf appears normal.