When infrared standard stars are used in radiation calibration for a ground-based large-aperture infrared photoelectric system, it can not determine the radiance responsivity of each pixel and shows a poor adaptability for non-uniformity of the system. To solve this problems, a combined radiometric calibration method based on infrared standard stars and the small-aperture blackbody was proposed. The infrared standard stars were taken as an outer reference source to calibrate the radiance responsivity of the total optics,and the blackbody was taken as the inner reference source to calibrate the radiance responsivity of the partial optics. Finally, the transmittance of the front optics was calculated based on the inner and outer calibration results, and the radiance responsivity of the total optics was calibrated in pixel levels. Several experiments were performed to inverse the illuminance of the infrared stars. The results show that the maximum relative inversion error of the proposed method is 15.89% and that from infrared standard star calibration is 15.92%, which means that the proposed method keeps more accurate than that of the infrared standard star method. Moreover, the radiance responsivity of the total optics corresponding to each pixel is calibrated, and the results indicate that the proposed method overcomes the interference of system non-uniformity, improves the utilization ratio of the focal plane array and makes up the application defect of standard infrared stars.