In this study,based on the results of WRF model simulation with an NSSL microphysical scheme,which included prediction of cloud condensation nuclei(CCN) concentration and volume of graupel in hail,a hail storm that developed in Nanjing was simulated,and three different CCN initial concentrations were used.The variation of precipitation and hydrometeor,as well as the vertical distribution of the hydrometeor,temperature and wind at different stages of the storm's development,were investigated.The results revealed the following:1)Greater CCN concentration decreases the precipitation during the early stage,yet increases the precipitation during the later stage.2)Greater CCN concentration leads to the enlargement of the high dBZ area(>40 dBz) and the atrophy of the middle dBz area(<40 dBz).3)Greater CCN concentration increases the amount of snow and ice,decreases the graupel,and delays the appearance of the high peak of the hail amount.4)Increased concentration of CCN inhibits rain production,indirectly rendering the helium particles more prone to dry growth,with a lower average density.5)Greater CCN concentration suppresses an early warm cloud process,but promotes the production of snow and ice,which causes the hail storm to be stronger and last for a longer period of time.