Geo-Oculus is a study approached by European Space Agency in 2008 with the objective to enable observations of the global environment and security combining high resolution and real-time monitoring in geostationary orbit. Its main tasks are disaster monitoring (floods, large landslides and storms), fire monitoring, algal bloom detection and water quality monitoring. In addition, the Geo-Oculus also has the ability of collecting oil slick environmental information and monitoring erosion/sediment transport on the European shoreline. The Geo-Oculus has the capability of high resolution and real-time observing. It also offers the images in more than 20 spectral bands covering UV (resolution of 40m), VS (resolution of 21m), VNIR, MIR and TIR (resolution of 750m). The Geo-Oculus study is a significant pre-study of the high resolution and real-time monitoring geostationary satellite that will steadily establish the foundation of further detailed design and research.