In this research was investigated photo-degradation of low density polyethylene films by means of ZnO nanoparticles (pro oxidant).The surface of nanoparticles should be efficiently hydrophobic to achieve appropriate distribution of ZnO nanoparticles in polymeric matrix and their more effective distribution on nano-composite properties, as well as better interaction of these nanoparticles with polymeric material, and preventing their agglomeration. For this purpose, surface modification of ZnO nanoparticles was carried out by grafting free radical polymerization of polystyrene and polyacrylamide on to the surface. The presence of polymer on the nanoparticles surface was investigated by 15 and 40 %Wt. The surface modification results were characterized by FT-IR and TGA analysis, and TEM analysis used to investigate their morphology. The modified nanoparticles were added to low density polyethylene in 0.25 and 0.75 %wt, then the films was prepared in thickness of 35 0.7?m. The films containing of modified, unmodified anoparticle and the films without nanoparticles were exposed to ultra-Violet radiation by UV lump. Tensile,Weight loss and SEM tests were performed on all samples both before and after 50, 100 and 200 hours of irradiation. FT-IR and TGA analysis result that nanoparticles surface modified favorable also, TEM images showed uniform distribution of ZnO nanoparticles. The results of the analysis of nano composites showed that the samples containing nanoparticles had a higher rate of degradation than the nanoparticles without their effect, but their effect on the oxidation rate was not the same, and also, an increasing in the percentage of nanoparticles increased the degradation rate. Meanwhile, nanoparticles which modified by poly (acrylamide) in a 10% surface modification value have the most effect on the degradation rate, so that for the sample which containing 0.75% wt modified nanoparticles, the lost weight is 24% after 200 hours irradiation time , while for samples without nanoparticles, it is 1.5%. Also, the results of the tensile test after 200 hours of irradiation showed that the tensile strength and elongation were 2 MPa and 23%, respectively at the fracture point for the sample containing 0.75%wt nanoparticles modified by polyacrylamide. The SEM results from the morphology of nanocomposite surfaces containing nanoparticle confirmed the polymeric tissue degradation