Calibration plays an important role in infrared characteristic measurement.Calibration method of fixed-focus imaging sensor and adjustable focus imaging sensor are theoretically analyzed.Merits and demerits of different calibration methods are introduced.Zero meter calibration method is usually selected,it is convenient and can calibrate all pixels.The selection of calibration temperature is analyzed in target IR characteristic measurement,analysis results show that:when calibration temperature interval is constant,the calibration error changes along "W" shape with calibration temperature;The calibration error is limited when calibration temperature distributes both sides of measurement temperature,so calibration temperature is selected on both sides of equivalent blackbody temperature,and calibration error is smaller when calibration temperature interval is smaller.