Liu began his karting career at the age of ten and achieved his first successes in 2018, winning rounds of the China Karting Championship in Shanghai and Jinhua. The following year, he would go on to win the Asian Karting Open Championship in the X30 Junior class, competing against the likes of Gerrard Xie and Bianca Bustamante.[2]
Macao International Kart Grand Prix
2017
Liu set his debut in the Macao International Kart Grand Prix in 2017 with Mars Racing Team.[3] In the Mini Rok class of the Asian Karting Open Championship, Liu finished 19th in the final race.[4]
2018
Liu returned to the International Kart Grand Prix in Macao, again in the Mini Rok class of the Asian Karting Open Championship with Mars Racing Team.[5] Liu would conclude the weekend by finishing 7th in the final.[6]
2019
Liu made his last appearance in the International Kart Grand Prix in 2019 with Mars Racing Team, joining the Formula 125 Junior class of the Asian Karting Championship.[7] He would finish the pre-final in 23rd and 18th in the final.[8]
Formula 4
2022
Liu made his single-seater debut at the end of 2022, where he competed in the Lausitzring round of the ADAC Formula 4 Championship, racing for US Racing. He achieved a best result of 9th from the second of the three races.
He also participated in the final two rounds of the Italian F4 Championship for AKM Motorsport with limited success, achieving a best result of 28th in Mugello and finishing 55th and last in the drivers' championship.
2023
Liu started the year off in the newly-founded Formula Winter Series, competing for US Racing. He would end up 4th in the championship with three podiums and a fastest lap.
His main campaign was a full season of the Italian F4 Championship, also with US Racing. Liu struggled to be competitive throughout the season, scoring no points and having a best result of 13th on multiple occasions. He would end up 30th in the drivers' championship, the last of his full-time teammates.
^"鼓掌!深圳市厚德书院国际部学子刘瑞祺再获国际大奖!" [Bravo! Liu Ruiqi, a student from Shenzhen Houde's International Department, wins another international award!]. 国际教育前线 International Education Forefront (in Chinese). 18 May 2023. Retrieved 1 February 2024.
^"刘瑞祺:亚洲冠军赛车手的飞驰人生" [Liu Ruiqi: the flying life of Asia's champion racing driver]. 新浪教育 Sina Education. 16 December 2019. Retrieved 1 February 2024.