Abstract: The calibration technology for absolute spectral responsivity of the nearinfrared radiation power is investigated. An extended infrared-InGaAs (EIRIGA) photodiode was designed. The spectral responsivity of the EIR-IGA detector was measured to allow it to be a standard power-transfer detector working in the wavelength range of 1.2μm～2.5μm. This near-infrared detector was also calibrated by cryogenic radiometers before. The absolute responsivity of the EIR-IGA detector was calibrated in 1260nm, and the continuous relative spectral responsivity was measured with a new IR SCF system based on IR monochromator. The absolute spectral responsivity of the detector is obtained at last with the two steps.