In April 2011, he beat Hossein Vafaei 7–3 in the final of the Asian Under-21 Championship,[4] and in doing so earned a place on the main professional snooker tour for the 2011–12 season.

[7] Cao played Ryan Day in his next match and trailed 7–9 going into the final session, when his opponent won four straight frames in just over an hour to result in a 7–13 defeat.

[10] Cao qualified for the second ranking event of the season, the Australian Goldfields Open, by beating Paul Davison, Alfie Burden and Mike Dunn all by 5–2 scorelines.

[11] He received a bye in the final qualifying round due to Anthony Hamilton's withdrawal,[12] and then came through a wild-card match against Johl Younger once in Australia to reach the last 32.

[17] Cao could only win one more match during the rest of the season, culminating in the second round of World Championship Qualifying where he lost 10–7 to Zhang Anda, meaning he was unable to repeat last year's run to The Crucible.

[21] He faced world number one, Neil Robertson and, although he led 4–3 and made five breaks above 50 in five separate frames during the match, he was edged out 5–4.

[22] Cao won the first title of his career in winning the gold medal in the men's singles at the Asian Indoor and Martial Arts Games by beating Ding Junhui 4–2 in the final.

[23] Cao qualified for four more ranking events during the season but lost in the first round in each one, coming closest to progressing at the International Championship when he came back from 5–2 down against Ding to level before losing the final frame.

[26] He came close to reaching the quarter-finals of the Wuxi Classic for the second season in a row, after he defeated Mark King 5–1 and Ricky Walden 5–3, stating that he done some body building, jogging and gym work to try to improve his game.

[36] In the same season Cao reached the semi-finals of the European Masters (losing to eventual champion Judd Trump) and his second final, the Gibraltar Open, where he lost 4–0 to Ryan Day.

He was suspended from the tour on 25 May 2018, alongside Yu Delu and David John, pending an investigation into suspected match fixing.

Cao's ban expired in November 2020, but he was unable to play in the professional circuit as a top-up so entered into the CBSA China Tour.