Using the WRF (Weather Research and Forecasting) model, different impacts of complex ice phase and simple ice phase on the typhoon track, intensity, and precipitation enhancement when typhoon makes landfall are investigated based on two comparative experiments with or without graupel in hydrometeor during the microphysical ice-phase process under the ideal island topography. The results show the complex ice-phase process with graupel in the cloud microphysical process has a stronger seeder-feeder effect of the cloud, which has a significant enhancement on typhoon precipitation. When typhoon experiences the ideal topography, it increases the enhancement effect of precipitation caused by the seeder-feeder mechanism of the cloud. The diabatic heating of the typhoon eye wall in the lower layer forms a significant enhancement center, which makes the typhoon precipitation increase significantly. When typhoon lands and crosses mountains, the cloud microphysical ice-phase process causes the vorticity tendency to point to the northwest.