 He gradually established himself within the Changchun squad as they fought for promotion to the top tier, eventually achieving this in the 2005 league season when they came second in the league.Playing in the top tier, Cao found it difficult to start many games since the club brought in Elvis Scott and then Guillaume Dah Zadi as their main strikers within the club, nevertheless Cao found his role within the team as a prolific goalscorer coming off the bench and go on to win the league title in the 2007 season with the club.It was only with the introduction of Li Shubin as the team's new manager did Cao Tianbao actually establish himself as the club's first-choice second striker within the team and help guide the club to a runners-up position at the end of the 2009 Chinese Super League season.