On December 1, after six months of business trial operation and the "practical" test of typhoon, rainstorm and severe convective weather in the flood season this year, Fengyun 3 E, Fengyun 4 B and their ground application systems officially operated. As a member of the global observation business sequence, "Li Mingxing" Fengyun No.3 E satellite added "early bus" to the global numerical weather forecasting service. Fengyun 4B satellite fully played the role of "eagle eye" of the minute level 250 meter resolution regional imaging provided by the fast imager, and two satellites efficiently supported global monitoring, global forecasting and global services, serving the construction of the "the Belt and Road" and emergency disaster reduction. This is another expansion of the Fengyun meteorological satellite business operation family following the operation of the second generation geostationary orbit quantitative remote sensing meteorological satellite test satellite Fengyun 4A on May 1, 2018. Wang Jinsong, director of the National Satellite Meteorological Center, said that the two satellites had performed well in the "internship period". Now they have become "regular", which is a milestone in China's meteorological modernization process. As the world's first civil twilight orbit operation satellite, FY3E satellite fills the gap in satellite data observation of the global numerical weather forecast model in the twilight period. During the impact of typhoons such as "Plum Blossom" and "Ma An", the satellite's onboard instruments were used to carry out the application research of numerical prediction assimilation. The results show that the star has improved the prediction deviation of gravity potential height field, temperature field and wind field at all levels, especially at the middle and upper levels, further enhanced the interaction between observation and prediction, and improved the accuracy of path prediction. The satellite data assimilation also improves the prediction score of quantitative rainfall, and enhances the prediction ability of the numerical prediction system for precipitation. FY4B is the first operational satellite of a new generation of geostationary orbit meteorological satellite in China. During the trial operation, the satellite launched a total of 22 intensive observations, and its rapid imager mobile observation capability played an important role in the precipitation in North China, strong convection in Qinghai, northeast cold vortex, and typhoon emergency response. In particular, on August 8, experts and scholars from the China Meteorological Administration, the Hong Kong Observatory, the Chinese Academy of Sciences and Fudan University focused on the South China Sea Low, the predecessor of typhoon Mulan. A typhoon intensive observation test was carried out. Through the use of Fengyun 4B satellite, airborne downcast sonde and sounding balloon, the final test conclusion was consistent with the prediction conclusion given by the national weather conference on August 9, and the important role of intelligent intensive target observation was further verified. During the trial operation, FY3 E satellite pushed about 650GB data to the National Meteorological Information Center every day through data distribution, and continued to provide data services for users at home and abroad; Fengyun No.4 B Star has provided a sharing service containing 90 products through "Tianqing", and released 37 products through the website. After the official operation, Fengyun No.3 E will form a three-star network with Fengyun No.3 C and D stars to provide the numerical forecast model with observation data covering the whole world every 6 hours, so as to improve the accuracy and timeliness of the global numerical weather forecast. FY4B and FY4A will form a dual satellite network to further meet the needs of China and countries and regions along the "the Belt and Road" for meteorological monitoring and forecasting, emergency disaster reduction. Up to now, China has successfully launched two generations of Type 4 1