坡锐天坑位于泗孟田园东面不到两公里的峰丛之中，是东兰天坑群的典型代表。洞口直径约90余米，洞深422m，是由地下溶洞顶部经多次坍塌直至裸露出地面而形成的深井状或桶状负地貌，为目前国内已知深度最深天坑第四名。天坑底部有伏流发育，且有崩塌物堆积。山体上部发育一小型溶洞，溶洞另一端与天坑相连，在洞口可听见天坑坠石的声音。 Porui Tiankeng, located in the peak cluster which is less than 2 kmfrom the east of Simeng Field, is a typical representative of the Tiankeng group in Donglan. The mouth of the cave is about 90 m in diameter and 422 m deep. Ranked as the fourth deepest cave in China so far, it is formed by repeated collapse of the top of underground karst caves and then exposed to form a landscape shaped like a deep well or bucket. At the bottom of the Tiankeng, there are underground river and collapse deposits .A small karst cave is developed at the top of the mountain. The other side of the cave is connected with Tiankeng, and from the mouth of the cave, the sound of falling stone in Tiankeng can be heard.