Abstract: This paper presents a calculating methode that solves the ground resolution of the scanning radiometer for a satellite. This methode can be used not only for the case of geostationary satellite, but also for the case of satellite of lower orbit (usually sun synchronization)in which the scanning direction of the radiometer is perpendicular to the orbit itself. It has been proved that the sides of the ground resolution element is composed of a segment of circles when the earth is regarded as a global and that the sides of the ground resolution element is composed of a segment of ellipses when the earth is regarded as a ellipsoid.