Abstract: The Weather Research and Forecasting (WRF 4.2) mesoscale numerical weather prediction model was used to simulate a heavy snowfall in Beijing from 12 to 13 February 2022, and the spatial and temporal evolution characteristics of the snowfall were well reproduced. Based on the simulation data, differences in dynamic, thermal, and cloud microphysical processes between the northern mountainous and southern plain areas were analyzed, and the possible impact of complex terrain on the snowfall process was discussed. Precipitation particles were ice-phase particles accompanied by significant conditional symmetric instability in the atmosphere. The simulation results show that precipitation was stronger in the mountainous areas than in the plain areas. A comparison of dynamic and thermal conditions between the mountainous and plain areas shows that the divergence and vorticity fields in the mountainous area were stronger due to the existence of topography. These areas also exhibited higher vertical velocities and stronger perturbation potential temperatures than the plain area. Cloud development was more vigorous over the mountainous areas, characterized by dominant water vapor sink regions where the phase transition of water vapor was more active. Although ice crystals and snow were the main hydrometeor particles in the mountainous and plain areas, the contents of ice crystals and snow were higher in the mountainous areas. The dominant conversion processes for ice crystals in clouds included the nucleation and deposition of ice crystals, autoconversion of ice crystals to snow, accretion of ice crystals by snow, deposition of snow crystals, and sublimation of ice and snow crystals near the surface. The difference in near-surface water vapor conditions led to a stronger sublimation process of ice crystals and snow in the plain areas. In addition, the occurrence of supercooled cloud water generated by the activation of cloud droplets close to the near-surface layer below 1.5 km altitude promoted the deposition of ice crystals and snow and the accretion of cloud water by snow.