A new method is developed to calibrate the absolute spectral responsivity of infrared detectors in the spectral range 1μm to 3μm.The spectral responsivity of test infrared detector is calibrated in two stages with two types of primary standard detector.Firstly,a continuous spectral responsivity of test infrared detector relative to referenced detector is measured at the Infrared Spectral Comparator Facility (IR SCF) and the referenced detector is a cavity thermopiles detector which has a response invariability with wavelength in the spectral range 1μm to 3μm.Then,the absolute spectral responsivity of test infrared detector is measured in several wavelength points by the primary standard cryogenic absolute radiometer and discrete lasers.And then we can calculate the absolute spectral responsivity of test infrared detector at every wavelength.Calibration for TS-76 is carried out and a combined uncertainty is less than 0.95%.