In January 2017, Sun entered the national table tennis team of China, only sixteen months after being selected for the B team. Sun won gold in the women's singles and mixed team with
Wang Chuqin at the
2018 Youth Olympic Games in
Buenos Aires,
Argentina.
2019 In the 2019 World Team Cup, Sun came back from down 10–7 in the deciding fifth game to defeat
Mima Ito in the finals against Japan. In an interview in 2021, Sun referred to this match as her precious match.
2021 Sun started out 2021 as number two in the world rankings. However, after China's decision to withdraw from all international events until the Tokyo Olympics, Mima Ito passed Sun for the number two position in the world rankings. In April, ITTF amended the seeding system for the Olympics such that she would be seeded above Mima Ito.
2023 On October 1, in the women's singles final of the Hangzhou Asian Games, Sun defeated Japan's Hina Hayata 4-1 to win gold. This was also Sun's third gold medal after winning both team and mixed doubles. This marked China's seventh consecutive championship in the women's singles competition at the Asian Games.
2024 At the 2024 Paris Olympics, Sun won the first gold in mixed doubles for the Chinese table tennis team, as well as women's team gold and women's singles silver. At the closing ceremony of Paris 2024 Olympic games, Sun was selected to extinguish the Olympic flame as the representative of the continent of Asia, the first female to be selected for the role. ==Singles titles==