Abstract: In this paper,a novel natural 3D viewpoint control system designed and implemented to enhance the naturalness of the viewpoint control and to give users more immersion perception is presented.In our proposed approach,the user's head position is obtained in 3D space by employing stereo vision methods.Then the head motion is mapped as viewpoint changes.Moreover,viewpoint locking via user voice is supported through voice recognition.Our experiments demonstrate that the proposed system is effective in practices.