The Dragon VAT is an oval sinkhole with a long axis distance of 304 ~ 326m, a short axis distance of 178 ~ 183m and a depth of 335m; This depth ranks third in China and fifth in the world; The inner wall of the cylinder is like cutting, the pine and cypress lie horizontally in the wall seam, the ancient rattan hangs upside down, the bottom of the cylinder spits green all the year round, and a hundred birds contend; Because it is shaped into a natural large stone cylinder and the wonderful legend of the love between woodcutter and dragon woman is also spread, it is named dragon cylinder and is known as "the first cylinder in the world".