Abstract: A calibration method for infrared temperature measuring instruments is disclosed. The calibration method of the present invention comprises the following five steps: (1) Calibrating the heat-flux resistor of an infrared temperature measuring instrument so as to obtain its calibrated resistance value (2) Using a digital multimeter to measure the parameters of the components and relevant circuits of the infrared temperature measuring instrument (3) Placing the infrared temperature measuring instrument in a blackbody radiation furnace so as to measure a single-point parameter of the blackbody radiation amplifier because the blackbody radiation furnace can provide a standard blackbody radiation source (4) Using the linear equation to obtain two additional parameters at two other temperatures so as to obtain a linear curve of the blackbody radiation amplifier (5) Storing the calibrated parameters in the memory of the infrared temperature measuring instrument.