Abstract: In order to explore the effect of selenium on the qualities of postharvest cherry tomatoes and find the proper concentration,selenium with various concentrations were applied to the soil at several stage during cherry tomato development. Then the fruit qualities including fruit firmness,color,soluble sugar,acid,V_C and active oxygen metabolism related enzymes at harvest and during storage were analyzed. The results showed that,the contents of fruit firmness,soluble sugar and V_C of 2 mg/L selenium applied tomato fruits increased by 7.98%,5.29% and 11.32% compared with that of control group at harvest,respectively. During postharvest storage,2 mg/L selenium treatment could maintain better fruit qualities,promote the activities of peroxidase(40.01~64.24 U/g)and superoxide dismutase(36.94~186.39 U/g),decreasd ethylene evolution rate to 8.01 μL/kg·h at 21 d,and then postpone the fruit senescence. However,higher concentration of selenium treatment(3 mg/L)had negative effects on the active oxygen metabolism related enzymes at later storage stage and was not satisfactory for maintaining cherry tomato qualities. The activities of catalase,peroxidase and superoxide dismutase decreased by 11.93%,23.09% and 31.01% than control at day 42,respectively. 2 mg/L concentration of selenium could be applied to promote the qualities of cherry tomato fruits at harvest and during postharvest storage.