Abstract: National Eco-meteorological System in China currently is the most important integrated data and computing system for national eco-meteorological operations. It is officially put into application in 2023. Compared with the previous desktop system CAgMSS, this web-based system has advantages of convenient use, fast computing speed, rich functions and strong scalability. This network-based system is capable of calculating and providing services for various eco-meteorological monitoring and assessment functions, including vegetation eco-meteorological monitoring and assessment, grassland eco-meteorological monitoring and assessment, desert eco-meteorological monitoring and assessment, forest eco-meteorological monitoring and assessment, and ecological service function assessment. The system currently supports the production of various eco-meteorological business service products, such as regular products like grassland eco-meteorological monitoring and assessment, and desert eco-meteorological assessment, as well as irregular decision-making service products, such as afforestation forecasts, special materials for the Yellow River Basin, and special materials for the Yangtze River Basin. Since 2016, this system has provided numerous additional functions for National Ecological Meteorological Bulletin each year. The Bulletin summarizes nationwide plant vegetation growth throughout the whole year and the meteorological influences, and the ecological conditions along with the meteorological influences and ecological function areas. Results reveal that, in 2024, the eco-meteorological conditions in most grassland in China is higher than those in 2023, and the growth of grass in most grasslands are better than that in 2023, the grassland yield increases by 3.4% compared with that in 2023. The vegetation growth in 2024 increases by 1%-10% compared to 2023. The forest vegetation plays a positive role in soil and water conservation. The water retention capacity and soil retention volume in most forests are higher than those recorded in 2023. Among these regions, the water conservation volume in eastern Liaoning, northern Hebei, northern and western Jiangnan, and northwestern South China is 200 mm to 350 mm higher than in normal years. The soil retention volume of forests in eastern Liaoning, northern North China, most of the Yangtze River Delta, and northern South China is 200 t·hm^-2 to 500 t·hm^-2 higher than in normal years. The vegetation ecological quality index increases by 7% compared to the average of last year, marking the highest vegetation ecological quality since 2000. From 2000 to 2024, 91% of the country's vegetation ecological quality index exhibited an upward trend. This paper introduces the design architecture, algorithms of the system and the mainstream key technologies currently used in national-level eco-meteorological services involved in the system, with the aim of providing methodological and systematic support for the development of national-level and provincial-level eco-meteorological services.