Abstract: ob＜x＞jective To investigate the therapeutic effect of botulinum toxin A on postherpetic neuralgia and its effect on comorbidities of anxiety and depression.Methods A total of 100 middle-aged and elderly patients with PHN who met the criteria from December 2019 to January 2021 were randomly divided into two groups: Botulinum toxin A group (BTX-A group) and control group (C group). Before treatment (T0), 1 week after treatment (T1), 4 weeks after treatment (T2), 12 weeks after treatment (T3), pain digital Score (NRS) score, patient health questionnaire depression Scale (PHQ-9) score, generalized Anxiety Disorder Scale (GAD-7) score, respectively. After 12 weeks of treatment, the improvement of overall sleep quality score (SQS) in both groups was assessed, and the use of oral drugs and the incidence of adverse reactions were recorded.Results Compared with T0, the SCORES of NRS, GAD-7 and PHQ-9 in 2 groups at T1 to T3 after treatment were decreased, and the scores of NRS, GAD-7 and PHQ-9 in BTX-A group were significantly improved compared with group C at the same time point (P < 0.05). After 12 weeks of treatment, there was no difference in the dose of gabapentin between the two groups (P > 0.05), nor in the use rate of opioids (P > 0.05). There was no significant difference in the incidence of adverse reactions between the two groups (P > 0.05).Conclusion Botulinum toxin A can relieve pain in middle-aged and elderly PHN patients, and improve anxiety and depression to A certain extent