The invention provides a numerical simulation method and system for a thunderstorm electrification process. The method comprises the following steps: calculating a statistical relationship between anaqueous particle mixing ratio parameter and a meteorological factor; obtaining a thundercloud micro-physical parameterization scheme based on the observation data of the thunderstorm weather and the statistical relationship between the aqueous particle mixing ratio parameter and the common meteorological factor; and based on the statistical relationship between the mixing ratio parameter of the aqueous particles and the common meteorological factor and the thundercloud micro-physical parameterization scheme, carrying out numerical simulation of the collision electrification process of the aqueous particles. According to the method and the system, through numerical simulation, numerical prediction of important factors of thunderstorm electrification processes such as thundercloud positionsand space electric field distribution can be realized. Through numerical simulation forecasting of parameters such as tower-level and line-level lightning intensity, motion trails and cloud-to-groundflashover, power transmission channel lightning early warning with more comprehensive and finer forecasting elements and longer timeliness can be realized.