20％。High-voltage electrostatic spray tester was designed through combination of high-voltage electrostatic spraying and axial-flow air-assisted techniques with the fluid director applied for the experiment of spray. Experimental study for air flow field, droplet size, and deposition were performed. Results indicated that technology of axial-flow air-assisted electrostatic spraying can effectively decrease the droplets diameter, makes droplets distributing more uniform and deposition better，which reduces the environmental pollution. At the same time, the electrostatic function makes the droplets more activated, and improves the ability of absorption, with the increase in sterilization efficiency by about 20%.