R temperature measurement in electrical equipment is more and more used in temperature measurement, but accuracy of temperature measurement is susceptible to outside interference. The main factors affecting the accuracy of measuring temperature, such as environmental factors, equipment emissivity and distance coefficient, are analyzed, the solution has been put forward. In the environmental conditions under the condition of relatively unchanged ,change rule of the temperature value along with the temperature measuring distance changing from 0.7 to 5 meters is found, and temperature value is calibrated . The result after calibrating shows that the method is valid,and error of temperature is less than 0.7°C within 5 meters.