The design principle and method of infrared ray automatic detection system for grinding temperature are introduced. The Grinding Temperature Automatic Detector was designed. The system can complete temperature’s correct detection and display in the grinding field of grinding mill. All grinding mills in workshops are connected to center survey room by modern net communication technology. Center survey room can directly display and print temperatures of any grinding mill by computers, and give command to operators to adjust grinding parameters, to trim grinding wheel, to change cool strength, so that high quality and high efficiency grinding machining can be realized in the limited grinding temperature scope. For the detector, temperature detecting scope is 0~1500oC. It is identified that the relative detecting precision is less than 0.5%. The detector is connected with center survey room to form local area network, to transfer the grinding information rapidly and correctly.