The interannual variation of Australian high and its effect on the Asia-Australia monsoon circulation system for 1948—2002 are analyzed,in the context of NCEP/NCAR reanalysis data.Results show that when the Australian high becomes strong,members of the Asia-Australia monsoon circulation system,such as the cross-equatorial flow between 100°E and 160°E,the ITCZ,the West Pacific subtropical high,the Meiyu front,the South Asian high,the near-equatorial easterly jet,the monsoon meridonal circulation,and the Hadley circulation etc also become strong,thus leading to the strengthen of the whole system.