Due to the advantages of more intensiveness, long duration, repeatability, and task-orientation, robot-assistant training has become a promising technology in stroke rehabilitation. Regarding the upper extremity, the natural coordination called shoulder rhythm is the most challenge to the design of ergonomic shoulder exoskeleton. Based on kinematic analysis of movement of shoulder complex, a 10-degree-of-freedom (DoF) exoskeleton rehabilitation robot with six-DoF shoulder actuation mechanism driven by pneumatic muscle through Bowden cable transmitting force is proposed. The kinematic relationship between shoulder girdle motion and the humerus flexion/retroflexion and abduction/adduction was described. The compact mechanisms for cable tension and cable disconnect/connect respectively were proposed to realize the cable automatic tension and drive-unit/manipulating-unit detachment. In order to verify the manipulability of the proposed robot during assisting patient with performing activities of daily living (ADLs), the performance criteria, i.e., normalized dexterity measure and manipulability ellipsoid, are used to evaluate and compare with human upper extremity. The evaluated results confirm the ergonomic design of shoulder mechanism of the rehabilitation robot that can provide approximate dexterity of human upper extremity in ADLs.