Abstract: Vetiveria zizanioides, Medicago sativa, and Festuca elata are commonly used as greening plants on engineered slopes. The aim of this study was to determine the effects of drought stress on the seed germination, photosynthesis, and physiological and biochemical indices of V. zizanioides, M. sativa, and F. elata. Analyses of the drought resistance of these three plants will provide a reference for selecting species suited to community reconstruction and/or ecological restoration of engineered slopes (e.g. those created in hydropower schemes). Drought stress was imposed using polyethylene glycol (PEG) at 5%, 10%, 15%, and 20%, and seeds of V. zizanioides, M. sativa, and F. elata were germinated under this range of PEG concentrations. To explore the adaptability of the three plant species to natural soil water stress, their photosynthetic characteristics and physiological and biological indexes were measured under four treatments: normal water (soil moisture content 75%-80% of field capacity), mild soil drought stress (65%-70% of field capacity), moderate soil drought stress (50%-55% of field capacity), and severe soil drought stress (35%-40% of field capacity). The membership function method was used to evaluate the drought resistance of the three plant species. The number of germinated seeds and seedling vigor decreased with increasing drought stress for all three plant species. The higher PEG concentration significantly inhibited seed growth, and reduced the relative germination rate and relative germination index. In contrast, the seed relative germination rate and germination index of V. zizanioides were promoted in the 5% PEG treatment. The net photosynthetic rate (P_n), transpiration rate (T_r), intercellular CO₂ concentration (C_i), stomatal conductance (G_s), and water use efficiency (WUE) of the three species decreased to different degrees under drought stress. The largest decreases in P_n, T_r, and C_i under drought stress were in V. zizanioides, while the largest decreases in G_s and WUE under drought stress were in F. elata. The malonaldehyde (MDA), proline (Pro), and soluble sugars content significantly increased in all three plant species with increasing drought severity. As the severity of the drought stress increased, the largest increase in MDA content was in V. zizanioides and the smallest was in F. elata. The MDA and soluble sugars content in M. sativa leaves significantly increased and showed a strong response to drought stress. The increase in Pro and soluble sugars content in leaves was smaller in V. zizanioides than in the other two species. The drought resistance of the three plant species was evaluated based on their germination rate, germination index, and photosynthetic and physiological characteristics using the membership function method. The most drought resistant species was M. sativa, followed by F. elata, and then V. zizanioides.