Abstract: Most of the damage cases of large components of wind turbines are caused by abnormal equipment wear, and the wear particles generated by wear contain rich information about the operation of the equipment.Therefore, the detection and analysis of lubricating oil or grease used in large components of wind power equipment is an effective method to prevent equipment failure and abnormal wear.In this paper, the application progress of wear particle sensor, viscosity sensor, moisture sensor and other online sensors in the field of wind power is introduced.