In this paper, a conceptual design is presented to develop the prosthetic robot hand which can accomplish most typical activities of daily life conducted by amputees. This design is based on three novel actuation principles, which are called distributed actuation, dual-mode twisting actuation, and EM joint locking mechanism, respectively. First of all, the distributed actuation may simulate the effect of the distributed muscles in human finger and provides an additional design freedom to structurally maximize the fingertip force. Second, the dual-mode twisting actuation is considered for a new type of power transmission which allows large actuating force and high-speed motion. Third, the EM joint locking mechanism guarantees additional degrees of freedom to the under-actuated robot finger/hand. It may lead to the dexterous motions and stable grasps. Finally, based on the design concepts of the actuation mechanisms, we design a finger module for a high performance and develop a robot hand having the five finger modules.