Safety is the first priority in production. The situation is complex in the deep underground of coal mines, and safety accidents often occur. Wire rope is a kind of safety device. With the help of wire rope, the safety of miners can be guaranteed to a certain extent. It is a very important tool for mining production. However, the current detection of coal mine wire rope still relies on the data from the factory, and it is impossible to achieve nondestructive testing in use. This article aims to study the degree of wear of mining wire ropes to ensure the safety of miners as much as possible. According to the characteristics of the wire rope, any defect (rust, broken wire, broken wire, etc.) changes in the cross-sectional area of the wire rope will change the magnetic permeability of the wire rope. With the help of equipment, we can collect data on changes in the magnetic field (MF). Based on this experimental design, the steel wire rope is given an MF, and the magnetic sensor is used to monitor the MF signal and convert it into an electrical signal. According to the collected electrical signal analysis and judgment, the sensor model is constructed, the size and position of the wire rope cross-sectional change are deduced, and the defect of the wire rope is judged. The experimental results in this study show that the magnetic sensor is an effective measure to monitor the nondestructive degree of the wire rope, with a sensitivity of more than 80%.