Objective: To study the impact of De-qi ((sic), obtaining qi) and psychological factors on the efficacy of acupuncture treatment for primary dysmenorrhea, with an attempt to explore the relationship among De-qi, psychological factors, and clinical efficacy. Methods: The patients with primary dysmenorrhea were randomly assigned to a group of acupuncture with manual manipulation (manipulation group, n=67) and an acupuncture group without manipulation (non-manipulation group, n=64). Pain intensity and pain duration were used as measures for evaluating the therapeutic efficacy of the acupuncture treatment. De-qi, the sensations a patient experienced during the acupuncture treatment, was scored on a 4-point scale by the subjects. In addition, the psychological factors, including belief in acupuncture, the level of nervousness, anxiety, and depression, were quantitatively assessed. The personality of the subject was assessed using the Eysenck personality questionnaire (EPQ) and 16 personality factor questionnaire (16PF). Results: Complete data were obtained from 120 patients, 60 patients in each group. There were statistically significant differences in pain intensity (W=2410.0, P<0.01) and pain duration (W=3181.0, P<0.01) between the two groups. The number of De-qi acupoints (W=1150.5, P<0.01) and the average intensity of De-qi (W=1141.0, P<0.01) were significantly higher in the manipulation group as compared with their non-manipulation counterparts. The correlation coefficients between De-qi and therapeutic efficacy of acupuncture were greater than those between psychological factors and therapeutic efficacy. Conclusions: Compared with the psychological factors, De-qi contributed more to the pain-relieving effect of acupuncture in subjects with primary dysmenorrhea. Moreover, manual manipulation is a prerequisite for eliciting and enhancing the De-qi sensations, and De-qi is critical for achieving therapeutic effects.