This paper presents an analytical satellite echo model based on Kepler orbit assumption, which can be used for high resolution satellite ISAR imaging analysis. In this model, the relative motion between each satellite scattering point and radar is decomposed as the combination of the satellite orbital motion and satellite spin. And then the analytical range expression that the echo pulse of each scatting point traveled from the transmitter to the receiver is provided analytically. Furthermore, we provide the analytical function of the range, velocity and acceleration of the scatting points on the three-axis stabilization satellite based on the proposed model. The orbital prediction error verifies the validity of the Kepler orbit model assumption in the proposed model. The impact of satellite attitude control in high resolution satellite ISAR imaging is also analyzed with a simple simulation.