Lubrication system contaminated by cooling water in high-speed wire rod production line is the most common problem in all high-speed wire units in China at present A monitoring device based on electrochemical impedance spectroscopy (EIS) for real-time monitoring the moisture content change of lubricating oil in high-speed wire mill is designed and simulated in laboratory The results show that the device can accurately detect the water content in lubricating oil on-line, and can monitor the change trend of water content in lubricating oil in real time; The measuring device is not sensitive to the reaction of worn metal particles in oil, and the influence of contaminated particles can be ignored in use.