Abstract: The effects of controlled atmosphere storage with different O₂ and CO₂ concentration on postharvest physiology and fruit browning of ‘Suli’pears stored at（0±0.5） ℃ were studied. The results showed that when the CO₂ concentration was 0%, the decrease of O₂ concentration could delay the increase of relative electrical conductivity of ‘Suli’pear pulp tissue and PPO activity, the decrease of phenols, and the yellowing of fruit color, however1.5% O₂ concentration could cause the fruit damage, the increase of PPO activity and core browning index. When O₂ concentration was 5%, the increase of CO₂ concentration could effectively maintain fruit hardness and color, however 8% CO₂ concentration could cause the significant increase of fruit relative electrical conductivity, aggravated oxidation of phenolic substances in fruit core and pulp, the increase of browning index of fruit core. In conclusion,the appropriate threshold value of controlled atmosphere index for ‘Suli’pears storage was: CO₂＜2%, O₂3%～5%.