The utility model discloses a cable circuit tester, which belongs to the technical field of cable testers and comprises a tester main body, a control screen is arranged on the upper surface of the tester main body, two protective covers are slidably mounted at positions, right opposite to the control screen, of the upper surface of the tester main body, and the two protective covers are matched with the control screen for use. A mounting shell is fixedly mounted on the side surface of the tester main body, a rotating shaft I is rotationally mounted in the mounting shell, a gear is fixedly mounted on the outer surface of the rotating shaft I, and two toothed plates are arranged outside the gear in a meshing manner; the protective cover is arranged to be used in cooperation with the mounting shell, sliding unfolding and closing of the protective cover are achieved through cooperation of the first rotating shaft, the gear and the toothed plate in the mounting shell, then the protective cover is opened when the control screen needs to be operated, the protective cover is closed after use, and the control screen can be effectively isolated and protected; the problem that the control screen is easy to touch and damage due to external installation is avoided, and a good protection effect is achieved.