Taking Arabidopsis trained about six weeks as the material,UV-B radiation(1 kJ/m2/d) and He-Ne laser irradiation(wavelength 632.8 nm output power 5 mW·mm2, irradiation time 60 s) were used to process the material.The Arabidopsis were divided into four treatment groups including CK(not treated ),L(He-Ne laser) ,B(UV-B), and BL(UV-B +He-Ne laser).The experimental results show that enhanced UV-B increases the contents of MDA,O.－2and the activities of PAL, CAT,APX ,while SOD activity and the content of GSH decrease. But He-Ne laser irradiation reduces the contents of MDA and O.－2,the PAL activity, and increases SOD activity, APX activity, CAT activity, the content of GSH .In contrast to B group, both enhanced UV-B and He-Ne laser have similar results which indicated by He-Ne laser irradiation. The results prove that laser can improve the ability of antioxidant system in Arabidopsis.