In this study,based on routine weather and Doppler weather radar data,the characteristics of the synoptic circulation background and structure characteristics of the supercell hailstorm which had occurred in Xuzhou are analyzed.The results show that this event had a forward-tilting structure,namely the upper-level trough moved from west to east at 500 hPa,and the cold air moved toward the south interface with the low-level jet,which was favorable to the formation of an unstable stratification structure.The convective storm that caused the hail had a typical supercell structure,and a strong rotation mesocyclone.The mesocyclone lasted nearly 30 minutes,and the max shear level of the mesocyclone was continuously higher than the 0℃ thermal level.Further research found that the max values of the rotational velocity and azimuthal shear of the mesocyclone were in the middle and upper levels,the rotation of the storm tended to expand upward,and the rotation had an abrupt increase in middle and upper levels.The rotation in the middle and upper levels of the storm underwent a process of decreasing in size,and the rotation intensified before and after the hail occurred,while the rotation in the storm led to the characteristics of suspended high strong echo and prominent bounded weak echo.In addition,the vertically integrated liquid (VIL) was much lower in this hail event,yet the vertically integrated liquid (VIL) underwent an abrupt increase before and after the hail occurred.This phenomenon can help us to judge the occurrence of small hail in the future.