The influences of the canopy height and the spray volume on the droplet distribution in the upper and bottom of the cotton canopy were iscussed in this study. XAG P30 plant protection Unmanned Aerial Vehicle (UAV) was used as a spray tool and water sensitive paper was used as the droplet test card. The spray volumes by the UAV include 18.0 L/ha, 22.5 L/ha, and 30.0 L/ha. The average planting heights of cotton in the test areas are 0.5 m, 0.7 m, and 1.1 m, respectively. The results show that the droplets are more well-distributed in the upper part of the canopy rather than the lower part. The spray volume has a significant effect on the droplet distribution in the canopy. The coverage, deposition, and droplet density will gradually increase with the increase of the application volume. The droplet distribution in the 1.1 m canopy area is poor, but it can be improved by increasing the spray volume.