Objective: This study aimed to observe the clinical efficacy of long-term spinal nerve posterior ramus pulsed radiofrequency (PRF) in treating subacute herpes zoster neuralgia (HZN). Methods: A total of 120 patients with subacute HZN in the thoracolumbar region and back were equally randomized to the conventional PRF group (P group, n = 60), with a pulse of 180 s, or to the long-term PRF group (LP group, n = 60), with a pulse of 600 s. The patients’ baseline characteristics, the incidence rate of postherpetic neuralgia (PHN), and the dose of analgesics were compared between the two groups. Results: Based on the pain-rating index (PRI), the PRI-sensory, PRI-affective, visual analogue scale, and present pain intensity scores in the two groups were lower at T{}_2, T{}_3, and T{}_4 time points than at the T{}_1 time point after treatment (p 0.05). After 2 months, the dose of analgesics was significantly lower in the LP group than in the P group (p 0.05), and the incidence of PHN was considerably lower. Conclusions: Long-term spinal nerve posterior ramus PRF is a more effective treatment strategy for subacute HZN than conventional PRF. It can effectively prevent the occurrence of PHN.