Abstract: In order to solve the problem about the influence of non-uniform field-of-view(FOV) response of radiometer on the measurement results during the assessment of infrared target stealth effect, a method of calibration and measurement under the same solid angle was put forward. The influence of the FOV response non-uniformity on the measurement results caused by off-axis aberrations was eliminated by adopting the principle of the same optical path. The calibration and measurement of the IR target radiation intensity and other parameters was realized. Finally, we adopted standard blackbody as the measuring object, and the 3μm ~5μm integral radiation intensity was verified by using the proposed method. The result shows that the difference between the measured and standard values is less than 2%, and the measurement uncertainty is better than 3.7%(k=2).