Abstract: This study aimed to investigate the effects of calcium (CaCl₂) and GA₃ on alfalfa seedlings’ physiological characteristics under drought stress and to discover appropriate concentrations for alleviating plant damage. Alfalfa seedlings were cultured in sand. The tested concentrations for CaCl₂ were 0, 5, 10 and 20 mmol/L; for GA₃ they were 0, 50, 100 and 150 mg/L, also tested was a complex liquid of 10 mmol/L CaCl₂ with 100 mg/L GA₃ (CaCl₂:GA₃). These four treatments (T_1∶1, T_1∶2, T_2∶1 and Z_1∶1 respectively) were investigated under conditions of PEG-6000 drought stress. Results indicated that chlorophyll relative content decreased under stress, while relative electrolytic leakage and MDA, Pro, SOD and POD contents increased significantly. Appropriate concentrations of CaCl₂, GA₃ and complex liquid could alleviate the degradation of seedling chlorophyll and reduce the relative conductivity and accumulation of MDA that protect film stability and reduce the content of osmotic regulation substances. They can also maintain higher SOD and POD activity and significantly improve alfalfa seedling resistance to drought stress. Using the method of subordinate function, it was found that 10 mmol/L CaCl₂, 100 mg/L GA₃ and CaCl₂+GA₃ T_1∶1 performed better than 10 mmol/L CaCl₂ and 100 mg/L GA₃. The study concluded that the relative drought relief effect of the treatments from strong to weak was T_1∶1>10 mmol/L CaCl₂>T_2∶1>CK₁>T_1∶2>100 mg/L GA₃>Z_1∶1>CK₂.