A term for hailstorm development is added to the numerical cumulus model presented in an earlier paper [1]. Radiosonde and other data of 4 cases of rainstorms and hailstorms respectively, all of which occur over the ChangJiang(Yangtze)-Huaihe Valley in the warm months,are fed into the model,which is operated on a DJS-6 computer. The computed results approach what are observed in reality. The experiment shows that the model is fairly successful in identifying hails and the simulated macro-and micro-structure of the cumulus and its development process resembles those of the natural cloud.