Objective: To observe and compare the clinical effects of different electroacupuncture waveforms on primary dysmenorrhea. Methods: This was a prospective, randomized, three-group, parallel-controlled trial. Participants with primary dysmenorrhea were randomly divided into dense-sparse wave, continuous wave, and discontinuous wave groups in a 1:1:1 ratio. Two lateral Ciliao (BL 32) points were used. All three groups started treatment 3–5 days before menstruation, once a day for six sessions per course of treatment, one course of treatment per menstrual cycle, and three menstrual cycles. The primary outcome measure was the proportion with an average visual analog scale (VAS) score reduction of ≥50% from baseline for dysmenorrhea in the third menstrual cycle during treatment. The secondary outcome measures included changes in dysmenorrhea VAS scores, Cox Menstrual Symptom Scale scores and the proportion of patients taking analgesic drugs. Results: The proportion of cases where the average VAS score for dysmenorrhea decreased by ≥50% from baseline in the third menstrual cycle was not statistically significant (P > .05). Precisely 30 min after acupuncture and regarding immediate analgesia on the most severe day of dysmenorrhea, there was a statistically significant difference in the dense-sparse wave group compared with the other two groups during the third menstrual cycle (P < .05). Additionally, there was a statistically significant difference between the dense-sparse wave and discontinuous wave groups 24 h after acupuncture (P < .05). Conclusions Waveform electroacupuncture can alleviate primary dysmenorrhea and its related symptoms in patients. The three groups showed similar results in terms of short- and long-term analgesic efficacy and a reduction in the number of patients taking analgesic drugs. Regarding achieving immediate analgesia, the dense-sparse wave group was slightly better than the other two groups.