Degradable master batch(M/D) was prepared using mechanical oxidation during melt mixing process with high shear and under the presence of air. High density polyethylene(HDPE) thin film containing 40wt% of degradable M/B was prepared by inflation film processing. The degradation of thin film has been studied with thermal aging in air environment at 60℃, UV aging in an artificial weather-0-meter, outdoor exposure and water soaking aging at 35℃. Seasonal effect was examined by the loss of tensile properties and by morphology change obtained with scanning electron microscopy(SEM). The effect of water on UV degradation was examined by an artificial weather-O-meter. It was noted that water affects the UV degradation of film. The decrease of tensile properties in summer was observed to be faster than that of the other seasons.