Objective:To elucidate the effect and mechanism of ZhuSha AnShen pill on fear memory in conditioned fear rats. MethodsA total of 90 male SD rats were randomly divided into three groups:blank group, model group and administration group, with 30 rats in each group; rats in the administration group were given Zhusha Anshen pill suspension by gavage (the volume of administration was 0.9 ml per 100 g of rat body weight), rats in the blank group and model group were given equal amount of double distilled water, and rats in each group were continuously intervened for 7 days. The conditioned fear model was reproduced after the last administration. The effects of Zhusha Anshen pill on fear memory was investigated by observing the rigidity response time of rats via the conditioned fear monitoring experiment system and the plasticity of hippocampal functional structure was studied by electrophysiological experiments and transmission electron microscopy.  Results:Zhusha Anshen pill can effectively promote the extinction of fear memory in conditioned fear rats as manifested in the following:the response time of rigidity in the stage of fear memory acquisition and the phase of regression was significantly reduced; the exercise time and distance increased significantly; the amplitude of PS in the hippocampus reduced significantly (P<0.05, P<0.01); the number of synapses in hippocampal neurons increased, the structure of each part of synapse was intact and the boundaries were clear,the length of synaptic active area and the thickness of PSD in hippocampus increased obviously, and the width of synaptic gap reduced obviously (P<0.05, P<0.01); the structure of hippocampal neurons was complete and clear, the nucleus was large, and the organelles in cytoplasm were more in number with better shape.  Conclusion:Zhusha Anshen pill can promote the fading of fear memory and its mechanism is related to the protection of hippocampal neurons, the regulation of hippocampal synaptic structure and functional plasticity.