The wheat seeds were irradiated by a 20 MW·mm^－2 CO₂ laser for 1 minute,3 minutes,5 minutes and 7 minutes. In the stage of seedlings,3.10 kJ ·m^－2 UV-B was employed to irradiate seedlings for 7 hours under the condition of PAR 90 μmol·m^－2·s^－1,then the contents of GSH,AsA,MDA and the activity of SOD、CAT、POD enzyme were determined. The results showed that the CO₂ laser pretreatment could increase the contents of GSH and AsA and the activity of SOD、CAT、POD enzyme,but decreased the content of MDA. Thereby the effects of CO₂ laser pretreatment could restrain the wheat seedling lipid peroxidation by UV-B radiation,and it showed that the best treat-time is about five minutes.