To investigate the process of the hailstorm on 17 May 2000,some hail samples are collected,photos of hail slices are taken,and the characters of the band pattern,spectra and inner structure of the hails are analysed.Along with synoptic chart,hailstorm echoes and rawinsonde observation,the weather condition and atmospheric stratification under which hailclound form are analysed and hailstrom echoes are investigated.