In this paper, the augmented adaptive control problem of free-floating dual-arm space robot system is studied. First, the dynamic equations of free-floating dual-arm space robot system are derived through the Lagranian formulation. With the augmentation approach, the control inputs and outputs are expanded. Based on the above results, an augmented adaptive control scheme for dual-arm space robot system with unknown payload parameters to track the desired trajectories in joint space is developed. A simulation study of a planar free-floating dual-arm space robot system is presented. The simulation results show that the proposed control scheme is feasible and effective