Physiological process is essential for plant growth, and is sensitive to environmental change. The Minjiang River dry valley in the upper reaches of the Yangtze River is increasing as it is affected by human activity, environmental changes, and their interactions under global climate change scenarios. Water deficit is a major limiting factor in vegetation recovery in this region. Therefore, evaluation of the physiological and biochemical levels is important to determine drought stress adaptations in plants and the selection of drought-tolerant plants. The aim of this study was to investigate the adaptation mechanisms of selected shrubs to drought stress in the Minjiang River dry valley, and to provide a reference for selecting drought-tolerant shrubs. We selected six mountain shrubs from this region, including Hippophae rhamnoides, Bauhinia faberi, Sorphora davidii, Caragana arborescens, Berberis sargentiana, and Cotinus szechuanensis. We evaluated changes of anti-oxidant protective enzyme activities, membrane injury indexes, and osmotic adjustment substances in leaves of these shrubs subjected to increasingly severe drought conditions, using pot experiments. The results showed that the responses of different anti-oxidant protective enzymes of these shrubs to drought stress and subsequent oxidative stress were different. In all six shrubs, superoxide dismutase (SOD) activities first increased and then decreased with prolonged drought stress, peroxidase (POD) activities increased gradually as drought stress continued, whereas catalase (CAT) activities increased in the middle and late stages of drought stress, indicating various protective enzymes could be playing inter-coordinating roles at different stress stages. Malondialdehyde (MDA) in all shrubs showed a slow increase with the prolonged drought stress, indicating that the membrane lipid peroxidation of cells gradually increased, and plants began to experience toxicity. With prolonged drought stress, the membrane permeability of H. rhamnoides and B. faberi initially increased, then decreased, and finally returned to the initial level at the end of the stress period, probably because these two shrubs obtained drought resistance by drought hardening. Membrane permeability of S. davidii and C. szechuanensis remained unchanged between 0 and 4 days when exposed to drought stress, and then sharply increased after 8 days, and then was maintained at a relatively high level. These findings implied that the membrane structure and function of these two plants was still intact and physiological activities could still proceed normally at early stages of drought stress; however, the cell membranes suffered serious damage during the middle stages of drought stress. In all six shrubs, proline contents increased with increased drought stress, indicating that drought stress resulted in proline accumulation and thus improved cell osmotic adjustment capabilities. Principal component analysis can provide a quantitative evaluation of the different physiological and biochemical indexes for the seedlings under drought, which indicated that the six shrubs could be ranked from the most to least drought resistant as follows:B. faberi, H. rhamnoides, C. arborescens, C. szechuanensis, S. davidii, B. sargentiana. The study revealed that all six shrubs positively responded to drought stress through improved antioxidant enzyme activity and the accumulation of osmotic adjustment substances, which could help to reduce reactive oxygen injury, improve osmotic adjustment capabilities, and reduce cell damage.