With Zhu Guanghu as the national teams coach Cao's international career would start to see him become a regular within the team and he was included in the squad that won the 2005 East Asian Football Championship as well as also being in the squad that took part in the 2007 AFC Asian Cup.
Cao's international career began under Zhu Guanghu's guidance, with his consistent performances leading to regular appearances in the team. He was a member of the squad that won the 2005 East Asian Football Championship and also participated in the 2007 AFC Asian Cup.