Xie Siyi, initially focused on the 10m platform with partner Chen Aisen, underwent a significant shift in his diving career due to a serious injury in 2012. Following this setback, he redirected his attention to the springboard events. At the 2015 World Aquatics Championships, Xie emerged as a new world champion by securing the gold medal in the 1m springboard event. His versatility was further demonstrated at the 2017 World Aquatics Championships in Budapest, where he claimed another gold, this time in the 3m springboard. In 2018, Xie made an impressive debut at the World Cup event in Wuhan, earning gold in the 3m synchro alongside Cao Yuan and an individual gold in the 3m event. The following year, at the 2019 World Aquatics Championships in Gwangju, South Korea, he continued his winning streak, clinching gold in the 3m springboard event and partnering with Cao Yuan for another gold in the 3m synchro. Xie Siyi's crowning moment came at the 2020 Tokyo Olympics, where he achieved double gold. He dominated the 3m springboard event, setting a Men's Olympics 3m springboard record with a total score of 558.75. Additionally, in the men's 3m synchro event, he partnered with Wang Zongyuan to secure another gold, showcasing his exceptional skill and dominance in the diving world.