Abstract: The movement of the fruit tree leaves in the gradient wind is analyzed in this article. The analysis show that the leaves can dodge, give away and turn in the gradient wind. The indoor and outdoor experiments show that the mere improvement of the flow velocity has little effect on the penetration of the droplets. On the contrary, it can make the droplets that have deposited on the leaves run away. The penetration and deposition of the droplets increase with the gradient wind. The gradient of the gradient wind must be raised in order to enhance the penetration and the deposition of the droplets. At the same time, in order to reduce the run-away of the deposited droplets, improve the uniformity of the droplets on all tree and enhance the medical effect, the maximum outlet wind velocity of the wind fan must be chosen and limited.