After a terse review of the history and status quo of the agricultural extension system in China, this paper analyses the advantages and disadvantages of the old system, then brings forward a fresh system which integrate scientific research, education and extension into it, and then describes its running mechanism and discusses some measures to realize it. In possession of a committee of experts who deals with the agricultural problems of the whole country to help decision-making, the Department of Agriculture is the highest administrative framework. The operating framework is composed of agricultural universities, scientific institutions of agriculture and agricultural schools, whose work directly connect the Department of Agriculture with front line of agricultural production. Then demonstration garden of agricultural science and technology at all levels which belongs to the operating framework as a site of research, agricultural education and extension is built and used to rebuild the former skeleton agricultural extension system.