To estimate the effect of acupuncture on idiopathic trigeminal neuralgia (ITN), we recruited 116 patients with ITN from December 2016 to April 2018 and further divided into them into two groups: acupuncture intervention group (n = 62) and sham control group (n = 54). Clinical pain, cognitive function, and quality of life (QoL) assessed with the 36-Item Short Form Health Survey (SF-36) were evaluated at the initial time of treatment, at the end of treatment, and 6 weeks after the treatment. Pain intensity, headache, and generalized body pain showed significant decrease both at the end of treatment and after 6 weeks of treatment when compared with initial time. The scores of the cognitive tests (Mini-Mental State Examination, Trail Making Test, Verbal Fluency Test, tracing score, and memory score) and five aspects of the SF-36 assessment (role emotional, general health, body pain, role physical, and mental health scores) showed significant improvement at the end of treatment compared with the initial time. Whereas after 6 weeks of treatment, the Mini-Mental State Examination, memory score, and Trail Making Test-A score and four aspects of the SF-36 assessment (vitality, bodily pain, mental health, and role physical) showed significant improvement when compared with the end of treatment. Acupuncture can be used as an alternative treatment to improve cognitive function and QoL of patients with ITN.