The purpose of this study is to validating a measure of Type A behavior pattern in children with computerized biofeedback system. In other words, the physiological reactions in different experimental situations were used to assess the construct validity of a measure of Type A behavior pattern in Children. The physiological reactions include heart rate, skin conductance, and skin temperature. The measure of Type A behavior pattern in children composes of three factors: time pressure, competition and achievement, aggression. This study includes two parts: experimental task and correlational measures. The experimental tasks will be designed to test these three factors. The correlational measures are divided into two parts: convergent validity and discriminant validity. In the experimental tasks, time pressure, competition, and aggression will be tested by time estimation task, crossing out number task, provocation task, respectively. In time estimation task, the dependent measures are time (second). In crossing out number task, the dependent measures are the number of 3s crossed out. In provocation task, the dependent measures are verbal and nonverbal aggressive behavior. However, the common dependent variables for all of three tasks are physiological reactions through computerized biofeedback system. A2 (classification-type A and type B)*2 (sex-female and male) factorial design is used. A total of 120 children will participate in the tasks. These three tasks will be presented in a fashion. The measure of type A behavior pattern in children (Lin, 1991) will be administered. 120 Type A and Type B children will participate in this study. Type A children performed in a more intense manner than did type B children on the time estimation task and the crossing out number task. Type A children had higher skin-conductance reaction than did type B children on the crossing out number task. Besides, the convergent validity will be produced by the correlation of a standard achievement test with a measure of type A behavior pattern in children. The discriminant validity will be produced by the correlation of a self-concept test and a creativity test with a measure of type A behavior pattern in children.