Abstract: Objective To investigate the effects of etomidate on the state of anxiety and cognitive function in mice with PTSD. Methods Male SD mice were randomly divided into five groups: control group (group C), PTSD model group (group P) and etomidate groups of low, medium and high dose (groups E1, E2, E3; 3, 6 and 12 mg／kg). Fear memory in mice is evaluated by fear Condition (FC), locomotor activity by open field (OF). State of anxiety is elevated by plus maze (EPM), learning and memory by spatial learning and memory by Morris water maze (MWM). Results Compared with group C, the percentage of freezing time in the FC were significantly increased (P<0.05) in group P; Compared with group P, the percentage of freezing time in the FC were significantly decreased (P<0.05) in group E3. Compared with group C, the residence time in the central gird of the OF were significantly decreased (P<0.01) in group P; Compared with group P, the residence time in the central gird of the OF were significantly increased (P<0.01) in group E3. Compared with group C, the proportion of time in the open arm of the EPM were significantly decreased (P<0.05) in group P; Compared with group P, the proportion of time in the open arm of the EPM were significantly increased (P<0.05) in group E3. . Compared with group C, the latency in the MWM were significantly increased (P<0.05) and the proportion of time in the target quadrant of the MWM were significantly decreased (P<0.05) in group P; Compared with group P, the latency in the MWM were significantly decreased (P<0.05) and the proportion of time in the target quadrant of the MWM were significantly increased (P<0.05) in group E. Conclusion Etomidate can significantly improve anxiety, enhance the ability of learning memory in mice with PTSD.