To study the cone-jet shape forming process and its impact factors by electrostatic spraying, combining with electrostatic spraying blade, the 2-D axisymmetric cone-jet physical model was proposed. Based on continuity equation and momentum equation in fluid dynamics, electric potential field equation and boundary conditions, the control equation of mathematical model was calculated by using Matlab and finite difference methods. The cone-jet shape, the electric field distribution for both internal and external of cone-jet and the electric field strength of the cone-jet surface were obtained. The calculated results showed the larger fluid flow and fluid surface tension, the larger the diameter and the top of cone-jet were. In the internal of cone-jet, the radial potential and electric field strength were gradually decreased, but the axial potential was increased slowly and the axial electric field strength kept invariant. In the external of cone-jet, the radial potential was stable and the axial potential uniformly changed. Fluid surface tension and fluid flow were inversely proportional to the normal electric field strength along the con-jet surface, but had no effect on the tangential electric field strength. 