Abstract: This study investigated the postharvest fruit quality and storability of ‘Xinyu’ sweet oranges harvested at three maturities so as to determine the optimal maturity and to promote technological support for its mass appeal. ‘Xinyu’ sweet oranges ‘Pengjia No. 39’ were harvested at 175, 185 and 195 days after full bloom on 14th October, 24th October and 3rd November, respectively. The fruit sample were stored in cold temperature (6 ± 0.5℃, relative humidity 85%-95%), and total soluble solid (TSS), titratable acidity (TA), vitamin C, MDA content, relative electrical conductivity, and autioxidant enzyme activities were determined. Decay rate and weight loss were recorded at different storage periods. The results showed that the fruit decay rate, weight loss, relative electrical conductivity and MDA content continuously increased, the content of TSS, TA and vitamin C gradually declined during cold storage. Decay rate in fruit harvested at harvest timeⅡ was significantly lower than those harvested at harvest time Ⅲ, and weight loss was significantly lower than those harvested at harvest timeⅠ and Ⅲ. Decay rate, weight loss, and MDA, REC were significantly and positively correlated. It is recommended that this famous citrus variety can be harvested in early November if they are to be marketed immediately after harvest or stored in cold for no more than 30 d. However, for long-term cold storage (up to 90 d), it is better to harvest the fruit in mid-late October.