Objective To evaluate the efficacy of pulsed radiofrequency(PRF)on dorsal root ganglion(DRG)guided by CT to treat thoracic postherpetic neuralgia(PHN). Methods 33 patients,who were 60-86 years old and suffered from the thoracic PHN for over 3 months to 18 months,were enrolled in our study from April 2014 to August 2015. The patients received PRF on DRG guided by CT to treat thoracic PHN. Three days later, the patients received the above mentioned treatment again. The visual analogue scale(VAS)was used to evaluate the pain degree at postoperative 1 d, 7 d,1 month and 3 months. The Pittsburgh sleep quality index(PSQI)and SF-36 were adopted to evaluate the quality of sleep and quality of life at postoperative 1 month, 3 months. Results Compared with those on preoperative 1 day, the VAS and PSQI scores after PRF were all down-regulated, whereas the parameters in SF-36 were up-regulated(P<0.05). No postoperative complications such as bleeding, pneumothorax and pulmonary infection were found in all patients. Conclusion Guided by CT, the PRF can be delivered at the location of DRG accurately and it is safe and effective.