Hebei, Shanxi provinces in North China suffered from severe drought in the spring of 2017. The drought had a certain impact on crop sowing and growth. Cloud seeding is helpful to alleviate drought. To carry out cloud seeding scientifically and accurately, based on the Cloud and Precipitation Explicit Forecast System (CPEFS_v1.0) and observational data, a typical low-trough cold-front cloud system precipitation process that occurred in North China from May 22 to 23, 2017, is studied. Choosing the Xingtai station in Hebei Province for an example, the cloud system structure at different precipitation stages and cloud seeding conditions are explored. The results show that when Xingtai is located behind the ground cold front and in front of the 700 hPa trough, strong rainfall occurs due to uplift of the front. The maximum rainfall in 10 minutes exceeds 2.0 mm, and the water vapor flux below 850 hPa at this stage is greater than 21 g·hPa^-1·cm^-1·s^-1. As the cloud anvil moves over Xingtai, the high-level cold cloud composed of ice and snow crystals transforms into a cold-warm mixed cloud. The mixing ratio of low-level cloud water, middle-level supercooled water and graupel is significantly higher. The main process of rainfall formation includes the collision of raindrops and cloud droplets, the melting of graupel. When Xingtai is located behind the 700 hPa trough and in front of the 500 hPa trough, the precipitation transforms into light rain formed by deep stratus clouds. The content of water vapor and cloud water in the middle and low layers decreases apparently at this stage. The rising movement mainly appears in the cold area and weakens obviously. The cloud system is still a mixed cold-warm cloud, but the mixing ratio of supercooled water and graupel decreases. The precipitation is mainly produced by the melting of graupel. The precipitation gradually dissipates after the 500 hPa trough transits. The cloud seeding time mainly occurs in the frontal uplifting-heavy rain period and the deep stratus cloud-light rain period. The seeding height is located at 4.0-7.9 km. And the strong seeding area is at the height of 4.0-5.5 km, the area with abundant supercooled water.