A ground moving target indication (GMTI) method for spaceborne high resolution wide swath (HRWS) synthetic aperture radar (SAR) systems is presented. First, the space time adaptive processing was adopted for clutter suppression followed by the traditional SAR imaging which yields the ambiguous images. Then all the moving targets including the real one and ghost ones were detected by the CFAR technique, and the real one was distinguished from all the imaging targets based on the space relationship of the ambiguous images. Finally, the moving velocity was obtained according to the azimuth position shift, which could be deduced from the range history of the moving target. The advantages of the method are its low computational burden and high accuracy. The spaceborne simulation data confirms its validity.