Xu Yunlong started his football career with Beijing Guoan in the 1999 season, making thirteen league appearances and quickly established himself as a versatile player.
[1] By the following season, he continued to gain considerably more playing time for Beijing and would often be used as a right back where his pace was quickly exploited; however, after several seasons, he played increasingly more at centre back and become an integral member of the club's defense.
On 26 February 2017, Xu retired from football and became the Commercial Director of Beijing Guoan.
[4] Under then manager Bora Milutinović, Xu's international career flourished by keeping previous right back Sun Jihai out of the national team during the 2000 AFC Asian Cup.
However, he was forced out of action due to illness and Sun regained his place within the team; nevertheless, his performances were still good enough to be called up the squad that participated in the 2002 FIFA World Cup.