It is important to study the responses of plants to water and shading stress and the physiological mechanisms responsible for stress tolerance for rational cultivation management. In the present study, the Chinese medicinal herb, Rhodiola kirilowii, was subjected to five watering and two shading treatments. The watering treatments were applied based on different soil water capacities, i.e., 80% (wet watering), 70% (normal watering), 60% (light drought), 40% (moderate drought), and 20% (severe drought). The shading treatments consisted of full light and shading with 85% black shade netting. Growth, physiological, and biochemical parameters of the treated plants were recorded. Under the different watering treatments, compared with the control, the chlorophyll content, stem dry weight, and stem mass ratio (SMR) increased significantly (P<0.05). In addition, plant height, total biomass, leaf area, leaf dry weight, leaf mass ratio (LMR), specific leaf area (SLA), leaf area ratio (LAR), and leaf area:root mass ratio (LARMR) increased, whereas the root:shoot ratio and root mass ratio (RMR) decreased. With increasing water stress, malondialdehyde, proline, and soluble sugar (Ss) contents increased, and superoxide dismutase activity initially increased but subsequently decreased. Under shading treatments, plant height, SMR, SLA, LAR, and LARMR increased significantly (P<0.05); chlorophyll SPAD values and leaf area increased, whereas total biomass, root dry weight, root:shoot ratio, and LMR decreased significantly (P<0.05), and stem dry weight and leaf dry weight decreased. Malondialdehyde content increased significantly, whereas proline content decreased slightly and Ss content decreased. Under water deficit, R. kirilowii showed increased antioxidant enzyme activity under moderate drought stress, but the threshold was exceeded under severe drought stress, when plants suffered stress-induced injury. Soluble sugars may represent the major osmotic adjustment compounds. Under shading stress, R. kirilowii increased SLA to compensate for decreased incident light. Thus, R. kirilowii altered leaf morphology, MDA content, protective enzyme activity, and osmotic adjustment compounds to ensure normal growth under exposure to environmental stress.