In this paper, we make an attempt to predict the location of a cable in next frame according to some parameters in current frame. At first, the initial condition is that the approximate location of cable must be given. From Hough Transformation, a high accumulated degree point in Hough Space is gotten. Afterwards, by inverse Hough Transformation, using that point, the location is detected and then cable is pointed out from its original image. Based on actual working conditions and performance indices, as well as the location in current frame, the maximum range of degree within which the cable may occur in next frame with high possibility is evaluated. Furthermore, a narrow range of location in next frame is confirmed according to the speed of robot. It is this narrow range that reduces the influence of the background on the detected object to the least. Therefore, the location of cable can be detected more accurately. Still more, as the final target of this project, an approach to detect the dangerous status of Cable is shown. In this approach, we want to distinguish the predict area into three parts with a simple area partition. By means of time sequence, the relative changes on the size of area which is between shadow and cable can conclude whether the cable is suspended in water.