The occurrence of agricultural diseases has been one of the restrict factors of sustainable agricultural development for a long time, and agricultural diseases early warning technology gradually becomes a hot issue in China and abroad. Based on the literature review, the important meaning of agricultural diseases early warning technology for agricultural development was presented. This article expounded the characteristics and classification of agriculture diseases early warning firstly. And then a systematical analysis and discussion were carried on the key technologies for agricultural diseases early warning information acquisition, mainly summarizing the internet of things and sensor technology, 3S technology, spectrum technology and pathogenic microorganism examination technology. And also an introduction of agricultural diseases early warning information processing technologies was made, such as image processing technology, expert system of disease early warning and disease prediction technology. Finally, the conclusion of the whole article was obtained. The results indicated that the integration and combination of mutitechnology would cover the whole agricultural diseases early warning area and get a higher accuracy of disease early warning；the acquisition of agricultural information was becoming precision and extensive; the early detection，diagnose and warning of agricultural diseases would be a new development direction; the agricultural disease early warning systems and equipment would be developed with lower cost; the realtime and online agricultural diseases automatic early warning will be an important research direction.