A scheme is presented in this paper for ground moving target indication of multichannel synthetic aperture radar (SAR) systems. “Dominant-velocity” is chosen as a valuable metric to describe the velocity map of the observed scene and the “dominant-velocity image” (DVI) can be generated via the developed spatial spectral processing technique. The mean and the standard deviation of each dominant-velocity are estimated from its neighborhood. Two different methods are proposed to derive the detection threshold in the plane: one is a nonparametric histogram approximation approach and the other is a parametric polynomial curve-fitting approach. The proposed ground moving target indication approach is a multistage one: the first stage implements the preliminary detection in the plane and a clustering technique is utilized to indicate potential moving targets, while the second stage implements the fine detection via a velocity estimation method based on maximum signal-to-interference ratio for the tagged targets. Finally, the effectiveness of the proposed method is verified by both simulated and real airborne SAR data.