In the multi-target observations using the ground-based large-aperture infrared telescope, in order to eliminate the influence of changing the system radiance responsivity caused by environment, and calibrate the radiance responsivity in short time during two observations, a fast radiance calibration method is discussed. A mathematical model and experimental procedures are set up. The radiance responsivity is calibrated, and the atmospheric transmittance is measured, based on the standard infrared stars. The illuminance of stars is inversed, which is known in advance, using the calibrated data. Data shows that the maximum relative error of inversion is 18.93% and it takes about 4 min to complete the experiment. As a comparison, the maximum relative error is 28.74%, and it takes about 17 min to complete the experiment, using the traditional method, that the radiance respoinsivity is calibrated based on the black body, and the atmospheric transmittance is calculated by Modtran. Results show that, compared with the traditional method, it takes less time to complete the experiment, and the relative error of illuminance inversion is smaller. The black body is not necessary, and it takes less cost.