Abstract: Under water-controlling treatment, drought resistance physiological characteristics of 2-year-old potted herbs of Hemerocallis fulva and Zoysia japonica under natural soil drought stress were measured and assessed by using membership function method. Results showed that: During the water-controlling course as the drought stress strengthened, the photosynthesis, transpiration rate, leaf chlorophyll content, soil water potential and leaf water potential of those plants all decreased while cytopermeability increased. Activity of superoxide dismutase (SOD) of H. fulva was in a "N" shape, and that of Z. japonica increased constantly. Soluble protein content of those two herbs first decreased and then increased. The change tendency of proline content of H. fulva first increased and then decreased, and that of Z. japonica was in a "V" shape. Comprehensive assessment of the two herbs showed that: Under drought stress, the performance of H. fulva was more excellent than Z. japonica.