Abstract: A calculating method of velocity-height ratio for image-moving compensation of a satellite photograph system is presented. When the scene on the ground is photographed from an aircraft, the velocity in the velocity- height ratio for the image-moving compensation is one of the ground relative to the aircraft, i. e. so called ground velocity. However, when the scene on the ground is photographed from a satellite, if the velocity was taken as one of the ground relative to the satellite, then the great error would be made. So, the authors have modified the definition of the velocityheight ratio. Such a new definition is suitable to be used for the photographing from aircraft as well as from satellite.Having considered the globe as a spheroid and the orbit of the satellite as elliptic, this paper derived the equations for calculation of the sub-sate llite point and the velocity-height ratio, finally compared such results with those under considering the globe as a sphere and neglecting the eccentricity of the orbit, the relative error of velocity-height ratio is less than 0.5%.