Abstract: To develop a computer application set up oriented at industrial CT for cable online detection. Through scanning along the x and y axes, the deviation is found to distinguish the media, and then the section image of each medium is constructed in real time, thus replacing the traditional method of armillary scanning to construct the image, and to complete the system detection. According to the conditions of detection, speed of the computer and other conditions, smoothing filter arithmetic is chosen to reduce the impact of noise on the accuracy of images. The system design and test is completed and the real time accouracy characteristics of online system are enhanced using the discussed methods in combination.