Effects of UV laser irradiation on structural modifications of SLG are studied. Nanometric-sized spherical carbon balls are formed in irradiated zone of SLG. Evident increase of ID/IG ratio indicates the increase of defects in irradiated SLG. Non-crystalline and oxidation process are revealed for SLG by laser irradiation. Optical transmittance of irradiated SLG only has a slight decrease by only ∼2%.