Using the fifth-generation Pennsylvania State University-National Center for Atmospheric Research(PSU/NCAR) Mesoscale Model(MM5 V3.5) and operational weather data,the heavy storm occurred on 17 April 2003 and the cold front rainfall occurred on 24~25 October 2002 in Shandong Province were successfully predicted.The data output from model,especially the quality content of ice(Q_i),graupel(Q_g),snow(Q_s),cloud water(Q_c) and rain water(Q_r) calculated by Reisner explicit microphysical schemes were analyzed to describethe characteristics and evolvement of cloud microphysic structures in two cases.The results shown that the mecro-synoptic dynamic action and the vapor transfer process play a key role in the development of the rainfall.The opportunity of artificial seeding in different conditions was discussed.