This paper presents the air is not super-fluid, the surface roughness, surface air rotates surged rotation. In this way, the ball in the course of rotation, rotation direction and the direction of the same side, the surface-led air flow and air flow outside the contrary, will offset part of the air flow rate, slows down, and low pressure will lead to increase. Another is the opposite situation, the pressure decreases. Superposition effects of the two together, the ball will be by force, the operation of the ball curved trajectory.Moreover, during the same power to a certain speed range, and speed is proportional. In this paper, based on the basic principles of fluid mechanics, analysis of the "banana" ball formation of the necessary conditions, in accordance with the actual situation of the establishment of a simplified model of the dynamics Xiangjiaoqiu from the center of mass movement theorem that the kinetic equation for the two approximation to the equations of motion by the arc of movement of the ball and its horizontal distance from the quantitative results.
Keywords：banana ball rotary ball fluid mechanical model deflection distance
