Abstract: The broken wire on surface of mine-used wire rope would tilt during operation, which may lead to the situation that the wire rope in operation scratches or takes away the inner wall of aperture in flaw detector, and even causes secondary damage to the wire rope, so as to affect detection results. For the above problems, a damage detection system for mine-used wire rope was designed based on ultrasonic ranging principle and strong magnetic detection principle. The system uses ultrasonic ranging device to detect tilting height of broken wire on the surface of wire rope. If the detection value exceeds the limit distance, an alarm would be issued, or else damage of the wire rope would be further detected by strong magnetic detection device. The test results show that in view of the set 20,30,35 mm tilting height of the broken wire, the detection errors of the system are basically not more than ±2 mm, which verify that the system can effectively and accurately detect broken wire on surface of the wire rope as well as its tilting height, so as to avoid the broken wire to damage the strong magnetic detection device caused by too high tilting.