Abstract: In capsule compression experiments on SG-Ⅱ facility, the variation of the hohlraum length affects the radiant intensity of the capsule equator and poles, thus the fuel is compressed to different shapes. We introduced the radiation hydrodynamics equations and numerical methods used in radiation multi-group diffusion modeling. Using the recently developed two-dimensional LARED-integration code, we accomplished the integrated simulation of compression distortion experiments of SG-Ⅱ hohlraums with different lengths in radiation multi-group diffusion approximation. The shapes of fuel simulated agree well with those in the SG-Ⅱ experiments, which shows that the radiation multi-group diffusion approximation could reflect the radiation uniformity in the hohlraum.