Abstract: Geosynchronous synthetic Aperture Radar (GEO SAR) has more advantages in moving target detection and imaging, but some problems need to be further solved. In this paper, a method of moving target detection, imaging and parameter estimation based on GEO SAR dual-channel and dual-carrier frequency is proposed. The generalized Keystone transform is used to correct the range migration of the moving target after clutter cancellation. After the Doppler parameters are estimated by discrete frequency modulated Fourier transform (DCFT) and Newton iterative method, the velocity sets obtained at different working frequencies are intersected to solve the problem of velocity ambiguity of fast moving targets. Finally, simulation results show that the method is effective.