Abstract: Objective:To study the effect of putrescine on physiological quality and antioxidant capacity on mechanically injured green bell pepper. Methods:Mechanical damage was simulated using 1 m high drop method, green peppers were soaked with 2 mmol/L putrescine and distilled water for 20 min, then stored at 20℃, the changes of physiological quality and antioxidant enzyme activity were determined. Results:Putrescine inhibited the green fading, maintained high contents of vitamin C and chlorophyll, inhibited the accumulation of malondiadehyde (MDA) contents, and enhanced the activities of peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX). Conclusion:Putrescine treatment could reduce the decline of physiological quality caused by mechanical damage of green bell pepper when stored at 20℃.