In order to solve the problem of insufficient adsorption rate of droplets on the target back via aerial electrostatic spray, this study proposed a high-voltage electrostatic generator to charge the liquids in two isolated water tanks with positive and negative charges respectively. A charge transfer loop was developed in space between the aerial electrostatic spray system and the ground. This method greatly enhanced the adsorption performance under outdoor conditions that 16.7% droplets density increased on the target front, a nearly fourfold destiny increased on the target back compared with the conventional UAV spray system. The target back-to-front ratio of droplet density was improved from 6.1% to 25.7%, which validated the satisfactory performance of the developed system.