Objective: To observe the effect of acupuncture on intelligence quotient (IQ) in children with mental retardation (MR). Methods: One hundred children with MR were randomly divided into an acupuncture group and a control group, 50 in each. There were 37 and 36 cases with complete data in the former and latter group respectively. Four-week treatment constituted a course, the comprehensive therapeutic effect of two groups was compared after 3 courses of treatment, and the influence of acupuncture on IQ was estimated. Results: The total effective rate in the acupuncture group was 78.4%, better than 30.56% in the control group, the difference being significant (P<0.01). Both groups were improved in IQ but the effect of the former group was better than that of the latter group (P<0.05). Conclusion: Acupuncture can obviously improve IQ of children suffering from MR.