This paper is concerned with the on-orbit-servicing free-floating dual-arm space robot and performs parameter identifications respectively for the robot base and the handling process of an unknown target satellite by one manipulator with the other manipulator hanging in the space. The identification is based on the conservation laws of linear and angular momentums, and it takes into consideration the linear and angle velocities of robot base centroid measured by the sensor that is mounted on the robot base. In the investigation, the space robot is symbolically modeled. Some methods to avoid the singularity of a set of linear equations during the identification of inertias are presented, and the effects of robot parameters on the identification are revealed. A numerical simulation is finally performed to verify the feasibility and effectiveness of the proposed parameter identification methods.