Electrode structure is an important factor affecting the charging effect of droplets. To study the effect of structure of ring electrode on the performance of electrospray, totally 12 kinds of ring electrodes based on the combination of different inner diameters (12mm,14mm, 16mm and 18mm) and thicknesses (1mm, 2mm and 3mm) were selected for experiments. In the experiment, the digital SLR camera was used for image acquisition, and the image was processed by software to obtain the spray cone angle. In the experiments, the voltage across the resistor was directly measured, and the droplet charge-mass-ratio was obtained by calculation. The effects of electrode structure on droplet charge performance and spray morphology were analyzed by comparing the spray cone angle and the droplet charge-mass-ratio. Based on the experimental condition, electric field of different ring electrode structures was calculated by numerically simulation, and its influence on the electric field distribution was obtained. The results showed that as the inner diameter of the ring electrode decreased or the thickness increased, the radial electric field strength around the ring electrode was increased, and the axial electric field strength did not change significantly. The spray cone angle and the specific ratio were increased as the inner diameter of the ring electrode decreased or the thickness increased. The variation of the thickness and inner diameter of the ring electrode changed the spatial electric field distribution, which affected the spray structure and droplet charging. The research results can supply some guideline for improving the charging performance of the droplets and rationally designing the electrostatic spray device.