The on-line monitoring of lubricating oil pollutants such as water,oxide and metal particles by oil quality sensor is of great significance to the normal operation of large industrial equipment.However,traditional lubricating oil sensor can not be used in many lubricating systems due to its low working pressure.A high-pressure multi-parameter lubricating oil sensor was designed,and taking the detection of water pollution in hydraulic oil as an example,the performance of the sensor under different pressures was tested.Repetitive experiments were conducted using an oil with a water content of 0.8%(mass fraction).It is found that the sensor can operate normally at the pressure range from 0 to 18 MPa,and there is a good linear relationship between the sensor output change and the lubricating oil pressure change.When the oil pressure remains stable,the sensor output has better stability.The sensor can normally detect the change of water content in high-pressure environment,and after high-pressure experiments,the sensitivity change of the sensor under normal pressure is less than 1%,indicating that the sensor has good pressure stability.