In this article, based on the analysis of the challenge by the knowledge economy to China´s social and economic development, the author points out that knowledge economy can texit and develop without the stable support by agriculture, only when the modernization of agriculture, industry and infrastructure realized can we enter the knowledge society smoothly. The total level and subsistent problems of agricultural science and technology are discussed, th^_e basic tasks that the innovative system for agricultural knowledge should undertake are also studied. The author believes that information and biology technology will be the two fundamental dustries in 21st century, the prospect and trend of their application in agriculture are also described. The author anticipates that the rapid development and intensive use of biology technology in agriculture will inaugurate 6 new fields for the research work of agricultural science and technology, which include the creation of new species, the application of the new fast breeding technology, the establishment of agricultural factory, the producing of new man-made food and feed, the exploitation for new energy and the searching for new space.