This paper presents a mathematical model of the projectile motion for physical education. Based on the principle of kinematics, the equation of projectile motion is developed. Then, by using differential calculus, a simple expression of relationships among the best angle of delivery, the maximum distances of delivery, the initial velocity of delivery, and the height of delivery point is introduced. According to this expression, we conclude that the best angle of delivery and the maximum distances of delivery are only related to the height of delivery and initial velocity of delivery. Finally, a diagram for the values of the maximum distance of delivery and the best angle of delivery are developed by computer. The results are used as a tool for the scientific physical education in the projectile motion (as shot put and hammer throw).