Ou debuted at the senior-level Chinese National Championships, helping the Guangdong team to the gold medals in the women's team and mixed team competitions.[3]
2019
Ou again represented Guangdong province at the Chinese National Championships. In the all-around, a fall on the uneven bars sunk her chances for the all-around gold, pushing her down to fourth place at that point, but after performing well on the balance beam she finished with a bronze medal.[3][4][5] She also won three more individual medals: gold on the balance beam, silver on the floor exercise behind Shang Chunsong and bronze on the uneven bars behind Liu Tingting and Cheng Shiyi.[6][7][8] Additionally, Ou and Liu led the Guandong province to win another gold in the provincial team final.[5]
In June, Ou was selected to represent China at the inaugural Junior World Championships alongside Wei Xiaoyuan and Guan Chenchen. While there, she helped China finish second in the team final, behind Russia and ahead of the United States. Individually, Ou finished third in the all-around behind Russians Viktoria Listunova and Vladislava Urazova and won silver on floor exercise once again behind Listunova. She also placed fifth on uneven bars and eighth on balance beam after a fall.[9]
After the postponement of the 2020 Summer Olympics due to the COVID-19 pandemic, Ou increased expectations for her senior debut by showing upgrades on all four events at an internal test in early September.[16] She notably attempted a balance beam routine with a start value of 7.5, which was more than a point higher than the 6.4 start value of Simone Biles' winning routine at the 2019 World Championships.[17] She also showed a new double-twisting Yurchenko vault and stuck a new Silivas (double-twisting double tuck) on floor to win the internal test ahead of reigning World all-around silver medalist Tang Xijing.[18][19] However, a knee injury forced Ou to withdraw from the Chinese National Championships a few weeks later.[20]
2021
In July, Ou was selected to represent China at the 2020 Summer Olympics alongside Lu Yufei, Tang Xijing, and Zhang Jin.[21] Due to an Achilles injury, she only competed on the vault, uneven bars, and balance beam during the qualification round where she helped the Chinese team finish third.[22][23] She did not qualify for any individual finals.[22] In the team final, Ou fell on her double-twisting Yurchenko vault and the Chinese team finished seventh.[23][24] Ou later competed on the 2021 Chinese National Games, finishing first in floor exercise and team final, and second in the all-around. She underwent surgery for her elbow and her ankle injuries afterwards and returned to her provincial team to recuperate.
2022
At the Chinese National Championships Ou placed second in the all-around behind Tang Xijing. Additionally she placed first with her team, third on balance beam and fifth on floor exercise.[25] In October, she competed at the World Championships in Liverpool. China placed sixth in the team final, while Ou placed seventh in the all-around and sixth on balance beam after a fall.
2023
At the 2023 Chinese Artistic Gymnastics Championships, Ou qualified into the all around, beam, and floor finals in 2nd, 3rd, and 1st position respectively. She placed second in the all-around final behind Qiu Qiyuan and ahead of Zhang Qingying, as well as first with her team, third on balance beam and fourth on floor exercise after making minor mistakes.[26] In August, Ou compete at the 2021 Summer World University Games in Chengdu, China along with Wei Xiaoyuan, Du Siyu, Luo Huan, and Zhang Jin. She qualified into the all-around, beam, and floor finals in first position. Ou placed first in the all-around ahead of teammate Luo Huan and Japanese gymnast Ayaka Sakaguchi. She also placed first with the Chinese team, and in the balance beam and floor exercise finals. In October, she was selected to compete in Antwerp for the 2023 World Artistic Gymnastics Championships alongside Qiu Qiyuan, Zhang Qingying, Zhou Yaqin, Huang Zhuofan and Wu Ran. She qualified into the individual all around and team finals. Team China finished in 4th place behind the United States of America, Brazil, and France. During team finals, Ou injured her foot on her first event which led her to withdraw from the all around finals.
^Lu, Yuchen; Shen, Nan; Niu, Mengtong (3 July 2021). "步步为赢——中国体操队东京奥运会大名单诞生记" [Step-by-step to win – the creation of the Chinese gymnastics squad for the Tokyo Olympics]. Xinhua (in Chinese).
^ ab"Artistic Gymnastics Results Book"(PDF). Olympics. The Tokyo Organizing Committee of the Olympic and Paralympic Games. 8 August 2021. Archived from the original(PDF) on 11 August 2021. Retrieved 17 September 2021.