Mental illness is one of the most common complications among the intellectual disability and needs medication to stabilize. However, the domestic researches on this subject are quite few. This research explored the usage and National Health Insurance resource consumption of antipsychotics by the intellectual disability. Using 2007 National Health Insurance Reimbursement Database, claimants with ICD-9-CM codes 317-319, defined as intellectual disability, were selected as the study subjects. Subjects who prescribed ATC N05A medicine were screened and analyzed outpatient health care utilization. The prescription rate of antipsychotics among research subjects was 15.57 % in which the female's 16.61% is higher than the male's 14.89%. On yearly medical expense, the male is 866.7 dollar more than his counterpart; and as to the annual days of medicine prescription, the male is 16.2 days more than the female. The differences of degree of disability, copayment situation and residential area of claimants will affect the cost of medicine and the number of days of administration. After logistic regression analysis, we found receiving antipsychotics treatment of the intellectual disabled was influenced by personal characteristics and medical facility. In conclusion, the health authority should pay more attention to the availability of medical treatment for the intellectual disabled in countryside and remote areas. In addition, research on the trend on long-term antipsychotics treatment and effect on NHI resource allocation is recommended.