6-year-old ‘Hongmeiren’ citrus hybrid trees grafted on trifoliate orange （Poncirus trifoliata） rootstock were used to study the effects of different leaf/fruit ratios on the physiological and biochemical characteristics of autumn shoot leaves of citrus under protected cultivation.Three leaf/fruit ratios including low （LFR60） medium （LFR80） and high （LFR100） were set up.The physiological and biochemical indexes including the contents of mineral elements，metabolites of carbon and nitrogen，activities of key enzymes and antioxidant enzymes in the metabolism of carbon and nitrogen in autumn shoot leaves were determined.The results showed that the content of phosphorus，potassium，magnesium，starch in autumn shoot leaves of LFR80 and LFR100 were significantly higher than that of LFR60.The content of malondialdehyde，proline，ascorbic acid in autumn shoot leaves of LFR80 and LFR100 were significantly lower than that of LFR60.The activity of β-amylase，nitrate reductase，glutamine synthetase，ascorbate peroxidase in autumn shoot leaves of LFR80 and LFR100 were significantly higher than that of LFR60.The content of nutrients in autumn shoot leaves of LFR80 and LRF100 were more sufficient and the degree of stress was lower.It is indicated that controlling the leaf/fruit ratio of ‘Hongmeiren’ hybrid citrus under protected cultivation between 80 and 100 is beneficial for balancing vegetative and reproductive growth，delaying leaf senescence，and maintaining robust tree.