Abstract: The changes of foliar ascorbic acid and related physiological indexes in Zoysia japonica and Z. tenuifolia under drought stress were studied in a pot trial. The results showed that the dynamic change rules of foliar ascorbic acid and related physiological indexes were similar in Z. japonica and Z. tenuifolia under drought stress, but significant differences were still observed in these two cultivars. For example, the level and redox status of ascorbic acid in these two cultivars were increased at the early drought stress stages, and then decreased at the later drought stress stages, but the decreased time was earlier in Z. japonica compared with Z. tenuifolia. Downtrend of leaf relative water content and peroxidase (POD) activity were found under drought stress in these two cultivars, but the downtrend in Z. japonica was more significant, especially at the later drought stress stages. In addition, the decreases of chlorophyll a and b were significant in Z. japonica but not in Z. tenuifolia under drought stress. Moreover, downtrend of the leaf relative electric conductivity and MDA content were also found in these two cultivars under drought stress, but the downtrend in Z. japonica was more significant. On the other hand, the Rubisco contents decreased on the 3rd day under drought stress in these two cultivars, and no significant difference in the level of Rubisco was observed in Z. japonica relative to the control at the later stages of drought stress, while the difference was significant in Z. tenuifolia. All these results showed that the increase of foliar ascorbic acid and POD activity in Zoysia under drought stress may delay the degradation of Rubisco and chlorophyll content and relieve the injury caused by oxidative stress and improve the drought-resistance. These results also confirmed that there are some drought-resistant difference between different Zoysia cultivars and the drought-resistant of Z. japonica is lower than Z. tenuifolia.