To further increase the laser-induced damage threshold of the fused silica elements, the effect of Magnetorheological Finishing( MRF) technology on the laser damage properties of fused silica elements was investigated under the condition of Hydrogen Fluoride(HF) acid dynamic etching process. Firstly, the fused silica samples were prepared by different processes and their surface roughnesses were measured. Then, the contents and depths of metal impurity elements before and after MRF processing were measured by Time of Flight- Secondary Ion Mass Spectroscopy (TOF-SIMS). The damage threshold was measured by 1-on-1 test method, and the damage morphology was observed and statistically analyzed. Finally, the reasons of increasing the laser-induced damage threshold of the fused silica by the MRF were analyzed. The experimental results were compared with that of the fused silica without the MRF. It shows that the MRF can increase the laser damage threshold of fused silica by 23.3%. Moreover, the content of metal impurity elements is significantly reduced, especially the Ce element which has a significant impact on the laser damage performance of fused silica is completely eliminated. It concludes that the MRF process can be used as a pre-treatment process for HF acid dynamic etching process.