The variety of surface emissivity of carbide insert P10 against temperature raise is calibrated with antitheses. The influence of high temperature object near the carbide insert and the open measurement environment of the thermal infrared imager on the calibrated values are investigated. Then the thermal images of turning tool’s rake face are continuously captured by an infrared imager in the designed turning experiment. In the analysis of thermal images, the influence of measurement environment is taken into consideration and varied emissivity values are used to analyze the temperature in different areas of the rake face. A series of measurement results of temperature field in the rake face are achieved and they are consistent with the conventional rules of turning researches.