The work aims to study the effects of gibberellic acid (GA3) of different concentrations on postharvest fresh-keeping effect of pitaya fruits. With pitaya as experimental material, the effects of 10 mg/L and 50 mg/L GA3 on the storage physiology and nutritional quality of pitaya at (7±1)℃ were studied. Compared with control, 10 mg/L and 50 mg/L GA3 treatment reduced the respiration rate, inhibited the increase of decay incidence and weight loss and malondialdehyde(MDA) content and polyphenol oxidase(PPO) activity, and delayed the decrease of total soluble solids, titratable acid and Vc content. The activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were enhanced, and 50 mg/L GA3 treatment effect was better than 10 mg/L. In summary, GA3 treatment delays the senescence of postharvest pitaya fruit and maintains its fruit quality during storage. The effect of 50 mg/L GA3 treatment is better.