Joint motion compensation can simultaneously correct the range shift and phase error caused by translational motion, which is convenient for high-resolution inverse synthetic aperture radar (ISAR) imaging. In ISAR imaging of space targets, the rotation of space target is the combination of the change of radar line of sight and the rotation caused by the target spin. Most works ignore the relative rotation caused by the target spin and thus deteriorate the performance of this promoting method. Therefore, this paper proposes a joint translational and rotational phase compensation method, which considers the effects of target motion and body rotation on joint motion compensation, constructs the compensation formula according to the minimum entropy criterion, and then uses the quasi-Newton method to solve the minimum entropy optimization problem.