The flexible pneumatic cylinder is a novel pneumatic actuator that can work even if the cylinder bends. The purpose of this study is to develop a simplestructured rehabilitation device using the flexible pneumatic cylinder. In this paper, the control and analysis of robot arm for the human wrist rehabilitation by using flexible pneumatic cylinder is introduced. The system consists of a slave arm, a master arm, a high-speed microcomputer, compact and inexpensive quasi-servo valves, a potentiometer and accelerometers to give the references for the attitude control. The control performances of the device were also investigated. Then, it is needed to improve the control performance of the devices. Therefore, the analytical model of the flexible pneumatic cylinder and the quasi servo valve with the embedded controller was proposed and tested for estimating the performance theoretically. The comparison between the theoretical and experimental results was also executed to confirm the validity of the proposed model.