There are abundant cloud water resources for development and utilization in the snowfall cloud system in winter in Beijing. For the needs of artificial snow enhancement research and full development of cloud water resources, the first annual snowfall in Beijing was observed on November 29, 2019. Data are analyzed, and numerical simulation is carried out. The macro-observation characteristics of the snowfall process are studied, and the atmospheric hydrometeor transportation characteristics and microphysical mechanism of the snowfall are also analyzed through the simulation results. The results show that the stable stratified cold cloud system affects the snowfall in Beijing. Water vapor and water condensate are mainly transported into the region from the western and southern boundaries of the Beijing area and flow out from the eastern and northern boundaries. The cloud hydrometeor transport channel for the snowfall cloud system accompanies a westward and southward component of the moist airflow. The water condensate in the snowfall cloud comprises ice crystals, snow, and a small amount of cloud water. The entire layer of the cloud system contains rich water vapor and runs through the entire snowfall period. In an ice-saturated environment, deposition of snow (Prds) are the main source of the snow, followed by the automatic conversion of cloud ice to snow (Prci) and the accretion of cloud ice by snow (Prai).