OBJECTIVE： To study the effects of sevoflurane on spatial memory ability and expression of brain-derived neurotrophic factor （BDNF） and tyrosine kinase B （TrkB） in hippocampus of mice. METHODS： A total of 54 C57BL/6 mice were randomly divided into anesthesia group and control group， with 27 rats in each group. Above 2 groups were divided into first day （first stage）， seventh day （second stage）， twenty-eighth day （third stage） sub-groups after anaesthesia， with 9 mice in each. In anesthesia group， mice were placed in a narcotic box， given sevoflurane 5％ for 1 min and then decreased to 2.5％ for 120 min； mice recoveried after anaesthesia completion. In control group， mice were always given pure oxygen. Morris water maze test was conducted in each stage. mRNA and protein expression levels of BDNF and TrkB in mice hippocampus were determined by PCR and ELISA after each stage. RESULTS： Compared with control group， platform quadrant and retention time of mice was prolonged significantly in first stage of anesthesia group， and the percentage of platform quadrant time was increased significantly， with statistical significance （P＜0.05）， but there was no significant change in the times of crossing platform （P＞0.05）. In second and third stage， there was no significant change in platform quadrant and retention time， the percentage of platform quadrant time or the times of crossing platform in anesthesia group （P＞0.05）. There was no significant change in mRNA and protein expression levels of BNDF and TrkB in mice hippocampus of anesthesia group （P＞0.05）. CONCLUSIONS： Sevoflurane anesthesia can strengthen spatial memory ability of mice in the early stage after anesthesia， but does not influence the generation of BDNF and TrkB in hippocampus.