The purpose of this study was to investigate the kinetic variables to improve the backhand drop motion for badminton players in elementary school. For this study, image analysis and EMG analysis for backhand drop motion was conducted a comparative analysis for each 6 badminton players in elementary, middle, high school. In order to find the statistical difference of kinematic and muscle activity variables of backhand drop, a one-way analysis of variance was conducted(p<.05). The results were as follows. In backhand drop motion, the racket head velocity of elementary school players was faster than high school players, the elbow angle of high school players was smaller than elementary school, middle school players. The abductor angular velocity of hand segment was the most slow in elementary school players. The trapezius muscle integral calculus electromyogram was bigger in elementary school players than high school players during the back swing. During the forward, the trapezius muscle average electromyogram and integral calculus electromyogram of high school players were the most small among three groups. Based on the results, for the effective backhand drop, players drag a shuttle cock downwardly with lots of extension velocity of wrist and relax the trapezius muscle in follow-through phase with lots of elbow flexion.