早期，地壳抬升，裂隙发育，地下河水溶蚀山体，将山体内部掏空，形成地下溶洞。在流水长时间冲刷作用下，溶洞所在山体发生坍塌，最终前后相通。后因地壳继续抬升、地下水位不断下降而逐渐显露于地表，形成似月亮形状的月亮山穿洞。

In early stage, with the rising of  crust and the development of cracks, the underground water eroded the mountain and hollowed the mountain, forming the underground cave. Under a long time of water erosion, the mountain where the cave lies collapsed and eventually connected the anterior and posterior cave. Later, as the  crust continues to lift and the groundwater level drops gradually, a karst cave shaped like the Moon, called Moon mountain karst cave was formed.