The aim of this work was to study the relevant parameters in electro-hydrodynamic (EHD) micro-jet printing technology for numerical analysis in cone-jet mode and dripping mode. In the cone-jet mode, the physical model of condensation-heating of capillary liquid jet was adjusted to be applicable for EHD printing; in the dripping mode, the concept of surface tension was introduced in the droplet formation process on the collector under pulse voltage for numerical analysis. The profile of Taylor cone in cone-jet mode was obtained using the numerical method, and the influence of the flow rate and net height on the jet diameter was focused; the correlations of droplet diameter and the pulse voltage frequency, the surface tension of the liquid in the dripping mode were emphasized, and the theoretic data were compared and analyzed with the experimental and experiential data. In the cone-jet mode, the jet diameter increased with the increase of the flow rate and the decrease of the net height under certain conditions; in the dripping mode, the droplet diameter decreased as the voltage frequency and the liquid surface tension increased respectively. The conclusions from numerical analysis showed good agreements with the experimental ones.