||This study aimed to investigate oxidative biodegradation behavior in oxo-biodegradable low-density polyethylene (LDPE) films. The oxo-biodegradable LDPE films were prepared by T-die twin extrusion with 1, 2, 3 wt% additives. It does not show a significant decrease in melting and crystallization temperature, and elongation and tensile strength compared to LDPE. The degradation behavior was investigated by a change in mechanical properties and molecular structure on heat or UV/heat exposure. The oxidative biodegradation at 50oC was able to observe the COO peak after about 50, 70, and 100 days, and the elongation decreased after about 130, 150, and 170 days. In accelerated weathering analysis at UV and 50oC, the elongation decreased after about 4 and 8 days, and the COO peak also increased significantly. Finally, the oxo-biodegradable LDPE films were decreased mechanical properties by 100%, and the molecular weight was decomposed from about 280,000 g/mol to less than 30,000 g/mol.