Purpose The purpose of this study is to investigate the difference of body kinematics according to velocity of ball in high school baseball players. Methods Ten high school baseball players participated in this study. They chose the ball speed themselves and threw the ball 10 times. Kinematic factors measured using the wearable Micro ElectroMechanical Systems sensor (MVN, Xsens technologies B.V., Enschede, the Netherlands) include the range of motion of the shoulder, torso rotation angular velocity and stride length. One hundred pitching data were divided into fifty high velocity pitching (The average of velocity of ball is 113.52km/h.) and fifty low velocity pitching (The average of velocity of ball is 94.82 km/h.). Kinematic factors of both pitching were analyzed by paired t test. Significance level of all statistics were set as p <.05. Results As shown in the results of measuring the range of motion of shoulder (external rotation and abduction), there were significant difference between the high velocity pitching and the low velocity pitching. Likewise, the results of torso rotation angular velocity showed a significant difference between the two pitching data and the stride length also showed a significant difference between the high and low pitching data. Conclusion In conclusion, range of motion of shoulder, torso rotation angular velocity and stride length are related to the velocity of the ball in baseball and should be considered for the ability of the pitcher.