水和可溶性岩石是形成喀斯特地貌必备的条件，当雨水或者地下水与地面碳酸盐类岩石接触时，就会有少量碳酸盐岩溶于水中。经过长时期的溶解侵蚀，最终形成东兰地区形态各异的喀斯特地貌景观。在喀斯特地貌下往往存在地下河、溶洞等景象。 Water and Soluble rocks are necessary conditions in the formation of karst landform. When rainwater or underground water meet with carbonate rocks on the ground, few carbonate rocks will dissolve in the water. After a long time of dissolution and erosion, there formed karst landscape of various shapes in Donglan region. Besides, there also exist other landscapes, such as subterranean river and karst caves.