Abstract: Based on the development of spaceborne synthetic aperture radar (SAR) image location technique, an analytic location arithmetic referring three ground control points (GCPs) is researched. This algorithm uses the earth model and the characteristics of SAR image to calculate the positions of target in the geocentric coordinates. And real-time location is available. Finally, based on GPS location data, 7 targets in Beijing are located and the location errors are analyzed. The algorithm is adapted to uncorrected spaceborns SAR image location without relying on any parameters of satellite platform and radar.