Along with the progress in automation and Industry 4.0, the use of industrial robots becomes much more popular. Meanwhile, the conventional manipulative devices, such as teaching pendant and joystick, are not intuitive enough and very time-consuming for task teaching. In facing more complicated tasks these days, it then induces high cost and demands experts with proper training. This paper thus aims to develop an intuitive manipulatory interface for assistance in simplifying the teaching process. We propose a wireless 3D manipulation system based on augmented reality (AR) with the tablet PC as the platform. The system allows the user to govern the movement of the real robot in a 3D space via a virtual one generated through the AR. We also develop several intelligent tools to assist the manipulation, so that accurate and collision-free path can be generated for the robot to follow for task execution. In addition, the system can also be used for offline training, which yields salient training effect for the operator. Experiments are executed to demonstrate the effectiveness of the proposed system, and questionnaires conducted to investigate user's response.