Abstract: A typical polar vortex circulation is established and developed during the period of 2003 September 3 to 14, on which the Xuelong exploration ship entered the Chukchi Sea of the Arctic Ocean for the Second Chinese Arctic Research Expedition. Most of the previous studies focused on the mean circulation structure and seasonal variation, this case, however, provides a necessary condition for studying its transient circulation situation and structure. In this paper, NCEP reanalysis data and the expedition observations are used for the synoptic analysis, including the development of the polar vortex, the circulation structures in the stratosphere, troposphere, and their relationship, together with the satellite remote sensing and meteorological data analysis from Xuelong exploration ship. It is found that the establishment and development of the polar vortex during the 2003 expedition period is characterized by a typical seasonal circulation transition from summertime to wintertime. It first appears in the stratosphere, and then transmits downward to the troposphere. In the stratosphere the vortex shifts westward and strengthens, while in the troposphere it moves eastward and southward.