Hao worked his way up by first playing for the Chinese under-17 national team in the 2003 FIFA U-17 World Championship and then progressed to the Chinese under-20 national team that took part in 2005 FIFA World Youth Championship. His performances were good enough for him to join the national team to play in the 2005 East Asian Cup where he made his debut on 3 August 2005 in a 2–2 draw against Japan. Under then manager Zhu Guanghu, his international career would flourish; however, he was not called up for the 2007 AFC Asian Cup due to illness. In 2008, Hao was eligible to play for the 2008 Summer Olympics squad where he started two of the three group games in the tournament.