Compared with the fixed-base manipulator system, kinematical and dynamical modeling and control of free-floating manipulator system (SBMS) becomes much more complicated. The primary cause is that there exists a deep dynamical coupling relationship between the floating base and the manipulator mounted on it. Firstly, in this article, generalized equation of motion of an n-DOF SBMS is built. Secondly, relevant attitudes of generalize coefficient matrixes, such as dynamical manipulability, are discussed. Then, in order to make the joints well follow a desired trajectory designed beforehand, a modelbased control method is proposed aiming at a 6-DOF SBMS. Finally, a simulation test is conducted to demonstrate effectiveness of the method mentioned above.