In this paper, we propose a method to select the observation position in visual servoing with an eye-in-vehicle configuration for the manipulator. In traditional visual servoing, the images taken by the camera may have various problems, including being out of view, large perspective aberrance, improper projection area of object in images and so on. In this paper, we propose a method to determine the observation position to solve these problems. A mobile robot system with pan-tilt camera is designed, which calculates the observation position based on an observation and then moves there. Both simulation and experimental results are provided to validate the effectiveness of the proposed method.