Abstract: As we entered the 21 century, after more than ten years of rapid development of high resolution remote sensing satellite, the earth observation satellite system has developed from the original single satellite observation model to the present light and small satellite constellation observation model. All-weather and all-directional earth observation can be realized. The satellite constellation, communication satellites, navigation satellites and aircrafts are linked through dynamic linking network to form space-based information network to realize intelligent earth observation in the future. To make the system more intelligent and improve perception and cognition of system as well as quick response ability, earth observation brain (EOB) is proposed in this paper. EOB is the intelligent earth observation system based on events perception. In this paper, the concept model of EOB and the key technologies needed to be solved are introduced in detail, and an example is given to illustrate the process of perceptual cognition in the primary stage of the EOB. In the future, EOB can observe when, where, what change of what object to push these right information to right people in the right time and right place. Globally all kinds of users will obtain related geospatial data, information and knowledge in real time through EOB.