Abstract: Using numerical model of mixed convective-stratiform cloud (MCS) in part (Ⅰ) in this paper and the averaged stratification of torrential rain processes.evolution processes.interaction of the two kinds of clouds.structure and the precipitation features in MCS to produce heavy rain are simulated and studied,and physical reasons of producing torrential rain are analysed.The results indicate that stratiform cloud surrounding convective cloud weakens and dissipates in developing and enhancing of the convective cloud.rainfall rate and water content of the stratiform cloud increase from near the convective cloud to lateral boundary.The numerical experiments find out that stratiform cloud provides a benificial developing environment for convective cloud.and saturated environment and the convergence field in the stratiform cloud make the convective cloud has longer life cycle.produce lasting rainfall with high intensity and intermittent precipitation with ultra-high intensity,these and the ice phase microphysical processes are main factors for torrential rain formation and MCS is a very effective preipitation system.