The Health Insurance Payment depended on the amount of outpatient. Each service brings income. However, depending on the amount of outpatient caused the problem of the excessive medical service. Besides of unnecessary costs and unreasonable distributions of medical resources, the unnecessary examinations and hospitalizing of the patient were increased. In order to control the cost and to enhance the quality, Taiwan Diagnosis related Groups was introduced step by step. It classifies the illness according to the ages, handling, complications and whether the patient would be hospitalized. Its payment depends on the kinds of illness. Therefore, the hospital must take the cost into consideration and the problem of the excessive medical service would be solved as the result.