Abstract: OBJECTIVE To analyze the association between postherpetic neuralgia and guanosine triphosphate cyclization hydrolase 1 (GCH1) gene polymorphism after herpes zoster virus infection and its risk factors after herpes zoster virus infection, and to construct a prediction model. METHODS From Jan 2021 to Dec 2022, 198 patients with herpes zoster virus infection admitted to Qingpu Branch of Zhongshan Hospital Affiliated to Fudan University were enrolled in the study, of which 56 patients with postherpetic neuralgia after herpes zoster virus infection were included in the study group and 142 patients with non-postherpetic neuralgia after herpes zoster virus infection were included in the control group. Clinical data of the subjects were retrospectively collected. The association between postherpetic neuralgia after herpes zoster virus infection and GCH1 gene polymorphism was analyzed. The risk factors for postherpetic neuralgia after herpes zoster virus infection were analyzed by univariate and multivariate analysis, and the predictive model was constructed. The receiver operating characteristic (ROC) curve was drawn to analyze the predictive value of the predictive model for postherpetic neuralgia after herpes zoster virus infection. RESULTS The genotype distribution of GCHI gene rs378641 in the study group had higher TT ratio, lower AT ratio and higher allele T ratio (P＜0.05). Multivariate logistic analysis showed that non-glucocorticoid therapy, the area involved, the increase of hospital anxiety and depression scale (HADS) score and GCHI gene rs378641 genotype TT were risk factors for postherpetic neuralgia after herpes zoster virus infection (P＜0.05). The above factors were incorporated into the prediction model as follows: Logit (P) =-10.653+0.782×non-glucocorticoid therapy+0.854×involved area+0.524×HADS+0.759×GCHI gene rs378641 genotype TT. The ROC curve of postherpetic neuralgia after herpes zoster virus infection was drawn to predict postherpetic neuralgia after herpes zoster virus infection. The results showed that when Logit (P)>13.56, the area under curve (AUC) was 0.902, with the diagnostic sensitivity of 85.71% and the specificity of 88.03%. CONCLUSION Postherpetic neuralgia after herpes zoster virus infection was closely related to the polymorphism of GCH1 gene, and many factors were associated with neuralgia after herpes zoster virus infection. The construction of prediction model had good value for predicting postherpetic neuralgia after herpes zoster virus infection, which could be used as the basis for prevention and control strategies.