Abstract： Objective To identify the effects of venlafaxiue on the acquisition and consolidation of fear extinction memory in conditioning fear memory extinction model.Methods Male Sprague-Dawley rats were treated with fear conditioning training in the A environment.Before the extinction training,all the experimental rats were given different doses of venlafaxine intraperitoneal injection.After 24 hours,all the rats test in the B environment.Results Repeated-measures ANOVA were conducted on the percent of freezing time for between-session extinction,test condition (F2,44 =458.958,P＜0.001 ) and VEN dose(F2,22 =43.026,P＜0.001 ) and a Test condition * Treatment interaction (F4,44 =31.363,P ＜ 0.001 ).For the within-session,post hoc comparisons indicated that the three groups that received different dose of VEN (0,20 and 40 mg/kg) did not differ from each other (P ＞ 0.05 ),indicating similar extinction following the post-conditioning.The rats injected with high-dose venlafaxine (40 mg/kg) intraperitoneally before extinction training showed pro,motion of between-subjects extinction of fear memory,but does not affect the within-subjects extinction.There was no significant catabolism in the rats injected with middle-dose (20 mg/kg).Conclusion The available date indicate that venlafaxine could promote the extinction of fear memory and there is a dose-dependent relationship of venlafaxine in the facilitation of fear memory.Our results could provide some clinical guidance for the treatment of post-traumatic stress disorder and panic disorder.