A hail event with a gale occurred on 5 June 2008 is analyzed from the aspects of the synoptic circulation background, physical quantities, and the characteristics of radar echoes and cloud pictures by means of observational data from the Meteorological Observation Network of China, Doppler weather radar data from the western Chongqing, and NCEP/NCAR 1°×1° reanalysis data. It is demonstrated that the vertical and horizontal wind shear and the clear sky solar radiation, which resulted in uneven surface heating, were apt to the vorticity genesis. The drycold air in the upper troposphere intruded into the lower layer favored the maintenance of convective instability, and the increasing of specific humidity and CAPE in the lower troposphere was essential to the development of the convective storm. The high potential vorticity (greater than 1 PVU) contributed to the genesis and development of the supercell storm (mesocyclone). The features of a supercell storm can be found, such as the strong overhanging echo core, false echo, mesocyclone, weak echo and echo wall, large echo intensity gradient, etc., and there existed the cumulonimbus plume and uprushing cloud top in the visible satellite imagery (VIS). Some forecast clues are concluded for supercell storms.