Fan started playing snooker at the age of 5 in Harbin. Just one year later he finished 5th in the National Youth Pool Championships. When he was 8 he finished 3rd in the National Youth Snooker Championships. A trip to Singapore at the age of 14 saw him reach the final of the 2015 Cuesports Singapore Snooker Open, losing to experienced local player Marvin Lim 5-3, after taking a 2-0 lead.
In July 2017, Fan won five out of the last six frames to beat top seed Luo Honghao 7–6 and win the IBSF World Under-21 Snooker Championship at the tournament held in China. With this victory he was awarded a two-year Main Tour card for the professional snooker tour.
He competed at the 2018 World Snooker Team Cup representing China with Zhang Jiankang but they lost to India 2–3 in the Round of 16.
At just 17, Fan was the youngest player on the professional tour in 2018-19. His first match was a 4-1 loss to Jack Lisowski in the Riga Masters, and his first win was against his practice partner Lyu Haotian 6-5 in the International Championship. However, he could only manage one further win in the remainder of the season, which finished in a 10-5 loss to Chris Wakelin in the World Championship.
Fan's best performance in the 2019-20 season came in the English Open. After a close win against Riley Parsons 4-3, he faced Chris Wakelin. At 3-3 the match ended on a respotted black in the final frame. After easy misses by both players Fan potted it to reach the last-32 for the first time. His run was ended by Shaun Murphy 4-0.
In subsequent tournaments Fan had further victories against Zhou Yuelong and Peter Lines. With the outbreak of COVID-19, the snooker season was suspended. Fan Zhengyi was one of only 4 Chinese players to stay in the UK, but was unable to practice due to lockdown restrictions. He played in the rescheduled World Championship, and beat amateur Dylan Emery 6-4 in the first round. He produced a fine attacking display in the second round against Dominic Dale, but eventually lost 6-4 after having led 4-3. Thus his season finished ranked 92, which meant he was relegated from the tour.
Fan has a very unusual technique. He is very left-eye dominant, and when playing the shot, his cue is to the left of his head. Before turning professional, he was a member of the Wiraka Snooker Academy and was coached by Roger Leighton.
Fan was also a promising table tennis player, but decided to concentrate on snooker. He is also a cat-lover. During the season, he lives in Sheffield and practices at the Victoria Academy.
Amateur finals: 2 (1 title, 1 runner-up)
- Fan Zhengyi at worldsnooker.com