OBJECTIVE： To study the improving effects of echinacoside （ECH） on spatial cognitive function in mice under hypobaric hypoxia environment and its mechanism. METHODS： Totally 60 mice were randomly divided into blank group （normal saline）， model group （normal saline）， positive group （Ginkgo leaf extract tablet，100 mg/kg） and ECH low-dose， medium-dose and high-dose groups （50， 75， 100 mg/kg）， with 10 mice in each group. Except for blank group， other groups were cultured in hypobaric oxygen chamber to simulate hypobaric hypoxia； they were given relevant medicine intragastrically once a day， for consecutive 7 d （Placing into hypobaric oxygen chamber immediately after medication）. Using the times of horizontal and vertical activities of mice in 2 min as index， negative emotions and spatial cognitive function were evaluated. Histopathological changes of hippocampus in mice were observed by microscopy after HE staining. The levels of SOD， CAT， GSH-Px and MDA in hippocampal tissue of mice were detected. RESULTS： Compared with blank group， the times of horizontal activities， MDA level were increased significantly in model group （P＜0.05）， while the times of vertical activities， the levels of SOD， CAT and GSH-Px were decreased significantly （P＜0.05）； the pyramidal cells in the CA1 area of the hippocampal tissue were arranged loosely， and many pyramidal cells were compressed and stained deeply. Compared with model group， the times of horizontal activities and MDA level were decreased significantly in positive group and ECH high-dose group （P＜0.05）， while the times of vertical activities， the levels of SOD， CAT and GSH-Px were increased significantly （P＜0.05）； the pyramidal cells in the CA1 region of the hippocampal tissue were abundant and closely arranged， and a few of them are constricted and deeply stained. CONCLUSIONS： ECH can improve spatial cognitive impairment of mice under hypobaric hypoxia environment， the mechanism of which may be associated with up-regulation of SOD， CAT and GSH-Px， down-regulation of MDA in the hippocampal tissue.