To investigate the effect of Taohong Siwu Decoction on the postherpetic neuralgia(PHN) model in rats.Methods:Sixty male SD rats were divided into a control group，a model group，and a treatment group according to the random number table method，with 20 rats in each group.The PHN model was induced in rats in the model group and the treatment group.After modeling，the rats in the treatment group received Taohong Siwu Decoction at 5 g/(kg·d) by intragastric administration.The differences in various indicators were compared.Results:The mechanical pain thresholds of the model group and the treatment group were lower than those of the control group 1 d，7 d，and 14 d after intervention(P<0.05)，and the mechanical pain thresholds of the treatment group were higher than those of the model group 7 d and 14 d after intervention(P<0.05).The levels of IL-1β，IL-4，and TNF-α in serum and spinal cord of the model group and the treatment group were higher than those of the control group(P<0.05)，and those of the treatment group were lower than those of the model group(P<0.05).The levels of IL-2 in serum and spinal cord of the model group and the treatment group were lower than that in the control group(P<0.05)，and that in the treatment group was higher than that in the model group(P<0.05).The levels of CD3+，CD4+，and CD4+/CD8+ in the model group and the treatment group were lower than those in the control group(P<0.05)，and those in the treatment group were higher than those in the model group(P<0.05).CD8+ and TGF-β levels in the model group and the treatment group were higher than those in the control group(P<0.05)，and those in the treatment group were lower than those in the model group(P<0.05).The expression levels of EphrinB2 and EphB2 proteins in the spinal cord of the model group and the treatment group were higher than those in the control group(P<0.05)，and those in the treatment group were lower than those in the model group(P<0.05).Conclusion:Taohong Siwu Decoction has a remarkable effect on the PHN rat model，which is worthy of attention.