Trigeminal neuralgia is the worst pain that human beings have ever experienced. Few researches have illustrated perioperative pain in patients with trigeminal neuralgia undergoing radiofrequency thermocoagulation (RFT) of the gasserian ganglion under local anesthesia. Because there are some undeniable drawbacks of using intravenous short-term anesthesia during the intervention repeatedly, some physicians keep patients awake throughout the puncture procedure, using local anesthesia. The purpose of this investigation was to examine perioperative pain in patients with trigeminal neuralgia undergoing RFT of the gasserian ganglion. Participants were 104 patients with classic trigeminal neuralgia. Worst pain intensity, mean pain intensity, quality of sleep, and analgesia satisfaction were evaluated for 24 hours before admission, 24 hours before operation, and 24 hours after operation. Intraoperative worst pain intensity was determined. Preoperative pain was serious, and preoperative sleep quality significantly and positively correlated with preoperative mean pain (r = 0.52; P = 0.00) and worst pain (r = 0.49; P = 0.00). Few patients (1.9%) responded to preoperative treatment, and the preoperative treatment obtained low analgesia satisfaction scores (3.9 [1.3]). Most patients experienced severe pain during cannulation under local anesthesia. No patients complained of pain during radiofrequency lesioning. The RFT of the gasserian ganglion alleviated pain obviously. Most patients (94.2%) responded to the operation, and the operation got high analgesia satisfaction scores (8.9 [0.7]). The results demonstrate that preoperative pain in patients with trigeminal neuralgia undergoing RFT of the gasserian ganglion is prevalent and undertreated and that intraoperative pain is severe under local anesthesia during cannulation.