Abstract: Stratiform clouds with embedded convection (referred to as “SEC” hereinafter), consisting of stratiform clouds and the convective clouds embedded within them, exhibit strong catalytic potential and are main targets for artificial rain enhancement. Due to the widespread agricultural drought in North China and the pressing need to increase water storage, conducting research on artificial rain enhancement for precipitation cloud systems in this region is particularly important.This study utilized the WRF model, coupled with an AgI seeding parameterization scheme, to perform numerical simulation experiments on AgI seeding during a precipitation event involving SEC that occurred in northern Shanxi on June 16, 2021. The simulation results were compared with satellite and airborne cloud physics observation data. With a good agreement in cloud top temperature and liquid water content, the catalytic precipitation process was simulated according to the actual seeding trajectory and dosage. Analysis of the simulation results indicates that the seeding operation significantly enhanced precipitation, with cumulative precipitation increases in local areas reaching 15-20 mm and a regional average rainfall enhancement rate of 9.6%. The nucleation process of AgI was primarily dominated by deposition nucleation, followed by condensation freezing nucleation, with immersion freezing nucleation being the weakest. Seeding AgI directly led to an increase in the concentration of ice crystals in the cloud, and the consumption of water vapor inhibited the production and growth of snow and graupel in the early stage. With the conversion of ice crystals to snow and the process of snow colliding with cloud droplets to form graupel, the total amount of snow and graupel particles increased. More snow and graupel fell below the zero-temperature level, melting into large raindrops, thus enhancing the cloud-rain collision process and ultimately leading to increased surface precipitation. Quantitative analysis of the microphysical processes affected by seeding shows that snow and graupel melting processes are enhanced by 27.26% and 20.53% compared to natural clouds, which are the main microphysical processes affected by seeding that affects the increase in precipitation. These results reveal and quantify the mechanism of seeding-influenced precipitation and cloud microphysical structure, which is helpful to understand the physical mechanism of artificial catalytic mixed cloud precipitation enhancement process, and providing valuable references for artificial influence on cold cloud weather operation in northern China.