This article mainly studies the technical application of infrared thermal imager in hydraulic systems,which uses its image temperature difference display technology to quickly identify the true liquid level of the oil tank,quickly troubleshoot abnormal temperature rise problems of hydraulic control valves such as electromagnetic directional valves,hydraulic control one-way valves,and pressure control valves,or problems such as loose valve closure and cooler blockage.This improves the efficiency of equipment maintenance personnel,inspection efficiency for equipment status,and accuracy of fault analysis and judgment.