The value of Pi is a very important and difficult research subject in mathematics. Many ancient Chinese mathematicians devoted themselves to the calculation of the value of Pi. And the achievements obtained by Zu Chongzhi in the 5th century AD could be regarded as a leap in the calculation of Pi. Zu Chongzhi was a great mathematician and astronomer in ancient China. Zu Chongzhi was born in Jiankang (currently Nanjing, Jiangsu) in 429 AD. His family had been studying astronomy and calendar for generations. He came into contact with mathematical and astronomical knowledge when he was young. In 464 AD, at the age of 35, Zu Chongzhi started the calculation of Pi.