The era of information agriculture is commencing in the new century. Information agriculture will be the research frontier for the reasonable exploitation and utilization of agricultural resources, increase of crop yield, reduction of agricultural costs, mitigation of environment pollution and improvement of the international market competitive power of agricultural products. It is foreseen that biological engineering and agricultural information technology will be the two technical backbones for China's agriculture in the new century, and will be essential to realize China´s agricultural modernization. The agricultural information science, technology and engineering are brifly summarized in this paper. In the 21st century, China's agricultural information science, technology and engineering should closely follow the international frontier and implement span development ：not only develop and apply existent agricultural information technologies, those internationally hotspot topics should also be studied and tested in advance, to speed up the agricultural modernization in China through the development of agricultural information engineering.

With the development and wide application of information science in agriculture as a new branch from agricultural technology system, agricultural information engineering has been gradually developed. It is a promising applied technology and an important technologyical support for realizing China's agricultural modernization. The scientifically combining of agriculture and information science created the science of agricultural information. The embodiment and application of information technology in all of the agricultural fields have pushed the development of agricultural information technology. Agricultural information engineering results from the research and application of agricultural information science and agricultural information technology. The basic contents of agricultural information science include the mechanism of agricultural information, information feature, information classification and coding, information reproducing and information linkage, etc. Agricultural information technology is associated with the technology of agricultural information resource acquisition and management, technology of information system, technology of information precise positioning, technology of agricultural auxiliary decision-making, computer modeling, simulation and virtual technologies, artificial intelligence and expert system technologies, automation technology, multimedia and network technologies, etc. The technological system of agricultural information engineering consists of agricultural information resource acquisition system, information management system, agricultural exploitation decision-making system, synthesis modeling system of regional resource exploitation, agricultural expert system and the virtual environment system of agricultural science knowledge innovation, etc.