Flinging, tossing, and throwing, are commen upper limbs motions in human childhoods. The kinematic parameters: percentage of time of motions, arm swinging speed, instant shot of main joint angle, are related to the numbers of throwing. The purpose of this study was to investigate the fifth and sixth grade students’ over-shoulder throwing with the motion staging. Objects are eight fifth graders and 8 sixth graders. Synchronizly retrieve children’s over -shoulder throwing motions for three times with two high-speed cameras (300 Hz). Divide motions into stride period, motion trigger period and windup period to analysis. Use the Kwon3D motion analysis software to analyse kinematic parameters. Inspect motion staging time with the throwing speed in Pearson's product-moment correlation. Using independent samples t-test, comparing the difference of fifth grade and sixth grade students throwing speed with the windup period of time percentage. Statistical level was set at α = .05. The results found that the total time of throwing and throwing speed is no related. The percentage of time of stride period was no correlation with throwing speed. The percentage of time of trigger period was no correlation with throwing speed. The percentage of time of the windup period with throwing speed was negatively correlated. In addition, the t-test of throwing speed of fifth grade and sixth grade students achieved significant. The t-test of time percentage of fifth grade and sixth grade students’ windup period of throwing was significant, too.