Objective To investigate the effects of radiofrequency (RF) temperature and length of needle tip on RF thermocoagulation in the treatment of trigeminal neuralgia (TN).Methods A retrospective analysis was performed on the clinical data of 160 cases of TN who were admitted to our department from August 2008 to August 2014 and underwent RF thermocoagulation. According to RF temperature and the length of needle, the participants were equally and divided into four groups, namely M, N, P, and Q.The continued thermocoagulation temperature was 75℃, 70℃, 75℃, and 70℃ and the length of needle tip was 5 mm, 5 mm, 2 mm, and 5 mm for the M, N, P, and Q groups, respectively. The patients of the four groups all received CT-guided percutaneous RF thermocoagulation of the semilunar ganglion.Results Compared with the preoperative Visual Analog Scale (VAS) score, the 1-day, 7-day, 1-month, and 3-month postoperative VAS scores all had significant improvement for the four groups (P<0.05). At each time point, in comparison with those in the N, P, and Q groups, the numbness score of the M group showed an increasing trend (P<0.05), and the numbness scores of the N group were significantly higher than those of the P and Q groups (P<0.05).Conclusions At the same RF temperature, the degree and scope of numbness and chewing weakness after operation in the group with the needle tip at 2 mm were significantly lower than those in the groups with the needle tip at 5 mm. It will achieve better clinical efficacy to select the appropriate length of needle tip and RF temperature with the consideration of patients' specific circumstance.