Abstract: To illustrate the morphological and leaf anatomical structure changes of Ilex cornuta var. fortunei and their adaptability to the changes of ambient air temperature, this study investigated the morphological and histological structure of the leaves of I. cornuta var. fortunei. The methods included field morphological observation and paraffin section. The results showed that as the temperature gradually decreased, the leaf color and relative electrolytic leakage changed significantly during the changes of ambient air temperature. The highest relative electrolytic leakage was 44.29% in March 2015. In addition, different leaf tissue structure indexes, including leaf thickness, upper and lower epidermis thickness, upper and lower cuticle thickness,palisade tissue thickness, spongy tissue thickness and ratio of palisade tissue to spongy tissue were examined. These different indexes increased initially and then decreased with the gradual temperature decrease. However, the spongy ratio tended to decrease, and then increase. These indicators changed significantly under different months. Therefore, the results indicated that improved adaptability of cold tolerance in I. cornuta var. fortunei relied on the changes of leaf structure.