Electrostatic atomization phenomenon for single droplet was shot based on high-speed video camera with tens of thousands of frames per second. The deformation of the charged and non-charged droplets, as well as their movements were compared and analyzed. The atomization mode at different voltages and the Taylor-cone length and cone angle changes under cone-jet mode were obtained. The results showed that droplet size decreased when the voltage increased, whereas its velocity increased with the voltage increasing. Biodiesel has bigger deformation rate than water under the same capillary, and the small droplet of biodiesel has larger deformation degree than big one. As the voltage increased, droplet went through dripping mode, the transition phase, cone-jet mode and multi-jet mode. In cone-jet mode, the cone length of Taylor-cone became direct ratio to the voltage, whereas the cone angle inversed to it. Conductivity had impact on the droplet movement, droplets with smaller conductivity moved along with the capillary axis, while droplets with bigger conductivity had both axial movement and radial movement.