The purpose of the paper is to investigate the physiological and biochemical mechanism of drought and low temperature stress in Sophora davidii seedlings. S. davidii seedlings were used as the experimental materials to evaluate the changes of anti-oxidant protective enzyme activities, membrane injury indexes, osmotic adjustment substances in leaves under increasingly severe drought in natural conditions, and late artificial low temperature treated, with pot experiments. The results showed that the relative water content of leaves decreased significantly with the increase of drought time, and the growth could be restored 2 days after rehydration. Moderate drought was beneficial to the accumulation of photosynthetic pigments, but the content of synchromes decreased in severe drought. Superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities first increased and then decreased with prolonged drought stress. The peak activity of SOD and POD was 458.85 U/g and 5.30 U/g, respectively on the 8th day, which was 142.53% and 68.25% more than CK respectively. Malondialdehyde (MDA) showed a slow increase with the prolonged drought stress, the peak value was 6.20 mmol/g FW on the 15th day, which was 108.75% higher than that of CK. Osmotic adjustment substances such as proline increased first and then decreased with prolonged drought stress, the peak value was 459.67 mg/g on the 10th day, which was 226.45% higher than that that of CK. Under drought stress and low temperature, photosynthetic pigment content of S. davidii leaves decreased significantly, and the changes of three protective enzymes activities (SOD, POD and CAT) increased first and then decreased, which were similar to those under drought stress. Malondialdehyde (MDA) and proline (Pro) showed increase gradually when cold stress continued. Three protective enzymes could play inter-coordinating roles at different stress stages for drought resistance and cold tolerance of S. davidii. The study revealed that S. davidii positively responded to stress through improved antioxidant enzyme activity and the accumulation of osmotic adjustment substances as proline, which could help to reduce reactive oxygen to the membrane damage. Drought stress could improve the adaptability to low temperature, which may be related to the enhancement of protective enzyme system and osmotic regulation ability.