Liu Hui was one of the most renowned mathematicians in ancient China. He was primarily known for his approximation of $\pi$, the ratio of a circle’s circumference to its diameter. In this submission, I will provide a summary of some life stories of him that are in general little known, including his work on $\pi$, one of his books named the “Sea Island Mathematical Manual”, his commentary on the classic Chinese mathematics book “the Nine Chapters”, his very clever approach of the proof of the Pythagorean Theorem, his work on the bicylinder or the double box-lid model and etc.