In the air-assisted spray, the change in the porosity of the canopy caused by the wind speed of the auxiliary airflow and the effect on the droplet migration were coupled, and the two ultimately affected the droplet deposition performance. Studying the effect of the coupling ratio of the two on the deposition performance can provide guidance for the optimization of air-assisted spray parameters and the improvement of spray patterns. Taking cotton in the full blooming period as the research object, and the different effects of the decoupling of the two on the droplet deposition behavior were analyzed by designing a decoupling test plan. Firstly, the deformation of cotton branches and leaves under wind load was calibrated with the help of a high-speed camera, and the fitting relationship among air velocity, leaf area and deformation was obtained. Through carrying out the wind load deformation test of the fake blade, it was verified that the wind load deformation error of the fake blade and the real blade was basically less than 17%. The plan of using the simulated cotton model to be applied to the air-assisted spray test was determined. Then, according to the 3/8 rule of the branch and leaf configuration of cotton growth and development, a cotton model of Scheme 1 in which the canopy porosity can be changed by wind load was built. The data of the airflow field in the cotton canopy was measured, and the deformation of branches and leaves under different wind speeds was calculated. Physical means were used to fix the deformation of branches and leaves, and a Scheme 2 cotton model was formed with fixed canopy porosity after wind load deformation. The cotton branches and leaves was fixed in the natural state and the canopy porosity was kept unchanged under wind load as the cotton model of Scheme 3. Finally, for the cotton models of the three test schemes, the auxiliary air flow velocity was changed to carry out air-assisted droplet deposition experiments. The test results showed that the migration effect of airflow on droplets was more favorable to the deposition behavior of droplets in the canopy than changes in canopy porosity. The effect of air flow on the movement of droplets increased the droplet deposition rate by 39.81%, and the change in canopy porosity increased the droplet deposition rate by 10.52%. The droplet transport channel formed by the increase of canopy pores was more conducive to the uniform distribution of droplets in the canopy than the transport effect of airflow on the droplets. The increase in the porosity of the canopy increased the deposition uniformity by 42.71%, and the transport effect of the air flow on the droplets increased the deposition uniformity by 1.10%. This decoupling method can provide a reference for the design of spray patterns for different crop canopy porosity changes.