The volcano park and its surrounding area have a history stretching back between 270,000 and 1,000,000 years when a series of volcanic eruptions formed this crater group. The tallest crater reaches a height of 222.2 metres above sea level and is 90 metres deep. It ranks among the world’s most intact inactive volcanoes.

Because the crater looks like a horse’s saddle it is sometimes called "Ma’an Jing" which means horse saddle ridge in Chinese. It is also the highest point in northern Hainan. Ten or more smaller inactive volcanic craters and vents surround the Ma’an crater. As a result of the eruption, geologists regard the area as having much scope as a museum for underground volcanic cave information.

Amongst the caves here, the most spectacular is perhaps that of the Daoist immortal Wolong. Even though it has yet to be fully developed, the visitor can still look around and explore the cave. The Daoist immortal caves are located about 4 kilometres from the Ma’an crater.

In the lava at the entrance of the cave can be seen the footprints of the immortals along with an elaborate memorial carved in the stone. Over the last fifty years, people have cleared the silt from the cave and discovered polished stone tools such as hatchets and chisels that were probably once used by our cave-dwelling ancestors. The Wolong cave lies about one kilometer from the main immortal caves and has a length of three kilometers, a height of seven metres and is ten metres wide. The cave is large enough to hold up to ten thousand people.