Abstract: Atmospheric correction is one of important steps to obtain the intrinsic radiance of the target for an infrared radiometry system. Traditionally, the mean to calculate atmospheric transmittance and atmospheric path radiance are calculated by an atmospheric radiance transport calculation software. A method based on standard reference direct amending atmospheric attenuation was proposed, which was applied for high precision precision measurement and inversion on a small target. The based principle and procedure of this method were introduced, and then the model of wide dynamic calibration was employed. Radiometric experiments were performed on a mid-wave infrared system with a 600 mm aperture. The radiometry results indicated that the radiance inversion precision for a small target, using the proposed method, is 0.97%-1.03%, while the precision using a conventional atmospheric transport calculation software method is 7.30%-7.36%, which demonstrates that the proposed method provides a high-precision result.