A convective precipitation is simulated by using a 3 D convective cloud salt seeding model. The model considers the microphysical processes between salt particles, liquid and ice particles. The simulation results indicate that seeding at a single time with seeding particle size of 20 μm can produce a good seeding effect, which can achieve 20% precipitation enhancement. Increasing the number of seeding time causes precipitation reduction. Graupel melting into rain is the main mechanism of raindrop increasing, and graupel collecting raindrop is the main mechanism of graupel increasing. The two processes get enhanced after seeding. Seeding brings changes to mixing ratios of cloud water, ice crystal, graupel and rain. The sizes of rain and graupel gain in seeded cloud.