By analyzing the EOF of reanalysis data,a northern-southern diploe is found in the upper troposphere geopotential height field of over the Asian-Australian monsoon region in the winter of Northern Hemisphere (NH),which is defined as Asian - Australian diploe (AAD) in this study, and a dipole intensity index (AADI) is defined. Correlation and synthetic analysis illustrated that AADI is closely related to the Asian-Australian region weather and climate in boreal winter. The index can reflect the simultaneous anomalies of temperature and precipitation on interannual and decadal scales in the boreal winter of Asia-Australia region. The superposition of the decadal and interannual signals is significant for the relationship between the AADI and climate change. The index can be used as an indicator of intensity of the Asian-Australian monsoon. In the years of strong AADI, the East Asia major deep trough is stronger, the subtropical high is weaker and the Alaska ridge and the westerly? jet are stronger than in normal years. Enhanced meridional circulation between high and low latitudes exists in the years of strong AADI. These relationships reflect the intrinsic link between the anomalies in the upper troposphere geopotential height and climate change in the Asia-Australia region essentially.