During the imaging of synthetic aperture radar (SAR)，there is a challenge for the deformation and calibration of the SAR imaging satellite payload reference relative to the satellite reference coordinate system.Based on the on-orbit working principle of SAR imaging satellite payloads，the definition of the beam center pointing for SAR imaging payloads is established in this paper.A geometric relationship model between the SAR imaging and the satellite attitude reference coordinate system is built.By rigorously applying coordinate transformation principles，a mathematical model for the relative deformation of the SAR payload imaging reference is derived.This provides a calibration method for the relative deformation of the SAR imaging reference based on attitude correction.Through on-orbit payload testing，the deviation data in the azimuth and range directions at different electric scan angles are obtained.Based on the satellite on-orbit data，the relative deformation of the satellite payload reference is calibrated.By uploading the calibrated parameters and comparing the image data before and after calibration，the image quality is improved by about 3 dB，verifying the feasibility and effectiveness of the method.This approach can effectively enhance the SAR image quality.