The aim of this study is to investigate the effects of brisk-walking on the behavioral problems of junior high school students with attention deficit/ hyperactivity disorders (ADHD). The study adopts the design of Pre-test and Post-test. The study is conducted by six ADHD students. The study lasted for 12 weeks. Every student walked for forty-five minutes in the early morning twice a week. Use the Student Behavior Rating Form as survey tool. The results of the study are as follows: In Post-test, the scores of the six main problems, including of behavioral impulse, attack damage, irregularities, anxiety, interpersonal and academic adaptation decrease compared with the Pre-test average. Also, the scores of the Behavioral Impulse between Pre-test and Post-test achieve the statistical significance. The conclusion is that the brisk-walking exercise has a positive effect on reduce the occurrence of impulsive behavior of junior high school students with ADHD.