Fast and accurate acquisition of navigation information is the key and premise for robot guidance. In this paper, a robot trajectory guidance system composed of a camera, a Digital Signal Controller and mobile agency driven by stepper motors is given. First the JPEG (Joint Photographic Expert Group) image taken by camera is decoded and turns to correspond pixel image. By binarization process the image is then transformed to a binary image. A fast line extraction algorithm is presented based on Column Elementary Line Segment method. Furthermore the trajectory direction deviation parameters and distance deviation parameters are calculated. In this way the robot is controlled to follow the given track accurately in higher speed.