The purpose of this study was to analyzed the effects of step aerobics on the physique and health-related fitness in the middle school girls by classified Sasang Constitution Classification. The Sasang Constitution was classified by QSCCⅡ and Sasang Pattern Identification Questionnaire and then confirmed by expert of this field, who was oriental medical doctor, attending to D oriental medical center in Busan. The subjects were Soyang-in 10, Soeum-in 10, Taeum-in 10, respectively total 30 middle school girls. Step Aerobics program performed 45min/day, 3day/week, during 12weeks with a RPE11∼15. The result was as follows; 1. The height was higher significantly than before exercise in Soeum-in, body weight was higher than that of the pretest values in the girl with Soyang-in, Soeum-in, and Taeeum-in, respectively but there was no significant. 2. The sit-ups, sit-and-reach test’s values were significantly improved than pretest, and %fat was decreased significantly in the subjects with Soeum-in and Taeum-in. Otherwise, BMI and LBM were slightly higher than pre exercise but there was no significant.