Abstract: A Cumulonimbus cloud with moderate intensity and a warm cloud base has been simulated by sing a dual-parameter cumulonimbus cloud model in the rainy season in Fujian. It is shown that the cloud precipitation process has two phases, the first one is a warm-rain process and the second with ice phase process. A series of numerical experiments of cloud seeding show that iceseeding or large droplet seeding cloud enhance the precipitation in the second phase. The effect of precipitation enhancement is concerned with the seeding pattern, the maximum can reach 24% of the total precipitation. In this paper, the mechanism of precipitation enhancement is also discussed.