This paper presents a mathematical model for the decisions of parameters in designing a tennis ball shooting machine based on analyses of aerodynamics of spinning tennis balls. The mathematical model is then simulated by MATLAB/Simulink in order to decide parameters for designing the shooting machine, including: heading angles, rotational speeds and powers of the motor driving the rollers, and ball shooting frequency. The new machine design will provide more flexible equipments for a wide range of tennis trainers and players.