In this paper, a two-level hierarchical intelligent control system is developed on a mobile robot to deal with target tracking and obstacle avoidance tasks. A stereo vision subsystem is first introduced. It can perceive video information in the environment to locate objects, including locating targets and obstacles precisely. This subsystem possesses two CCD cameras mounted on the top of a robot to obtain images from the surroundings. And then, based on the sensed image data in the indoor environment, a robot behavior decision-making subsystem with a fuzzy control strategy is proposed for target tracking and obstacle avoidance. Under this decision-making strategy, the robot can respond correctly to complete the desired task. Finally, site experiments are performed to show that the proposed schemes are feasible and effective.