Abstract: Effects of different controlled atmosphere treatments on the quality changes of lemon were investigated. In this investigation, the Eureka lemon fruits were used as the raw materials and stored in the controlled atmosphere boxes with the conditions of the temperature 4 ~ 8 ℃ and relative humidity 85% ~ 90%. Results indicated that Lemon fruits stored in atmosphere-controlled box of NO.2 and NO.3 exhibited the better quality ( Ⅱ, O2: 5% ~7%, CO2: 6% ~9% and Ⅲ, O2: 7% ~9%, CO2: 9% ~12%) for 20 days.The rate of weight loss and MDA content of lemon fruits were below 4% and 0.7 μmol/g, respectively.However, the contents of total soluble solid, titratable acid, vitamin C and total phenolic were above 7.30%, 4.6 g/100 g, 24.0 mg/100 g and 0.83 μg/g, respectively.Among them, the best storage quality of lemon fruits was observed in the treatment of NO.2 CA box. For the best treatment, the oxygen and carbon dioxide concentration were 5% ~7% and 6% ~9%, respectively.For the fruit quality in the best treatment, the rate of weight, content of total soluble solid, titratable acid, vitamin C, MDA and total phenolic were 3.34%, 7.38%, 4.77 g/100 g, 24.84 mg/100 g, 0.64 μmol/g and 0.84 μg/g, respectively.