Longtan Waterfall is also known as "Yulong Waterfall". It is located in the upper reaches of the Basui River on the southern foot of Mount Lao, about 1 kilometer away from the Shangqing Palace to the north.

The water source of Longtan Waterfall comes from the valley between Tiancha Peak with an altitude of 500 meters and the North Tianmen. The stream water traverses mountains and ridges, gathering dozens of brooks along the way and converging into a rapid current that rushes down. On a cliff-top platform about 30 meters high, it shoots out straight for several feet. After the water swirls and twists several times in mid-air, it finally forms a waterfall about 30 meters long and 5 meters wide, which then plunges along the 90-degree cliff into the blue pool below. With a majestic momentum, it looks just like a vigorous jade dragon, rising through the clouds and mists from the top of the cliff, roaring down and making the water in the pool splash in all directions. People in the mountains named it "Longtan Waterfall" according to its shape, sound and color, and named the deep pool under the waterfall "Longtan". The scene of "Longtan Waterfall Spraying Rain" among the twelve beautiful sceneries of Mount Lao refers to this waterfall.