Electro-Hydrodynamics printing technology, one of the printing technologies based on Electro-Hydrodynamics discharging theory, can be patterning of high resolution and high aspect ratio compared to conventional inkjet printing systems. We have been investigating to define the optimal regions of Electro-Hydrodynamics printing, including ink conductivity and viscosity, to generate a high aspect ratio of line patterns for printed electronics. First, various industrial conductive inks are ejected to find the most suitable ejection mode for feature of patterning using a gate electrode Electro-Hydrodynamics printing system. Most inks have poor ejection performance with spraying, but some inks exhibit a good pulsed jet mode for the neat patterning. In particular, it requires at most 10 -5 S/m of electrical conductivity of inks to be used for a stable pulsed jet mode of ejection; otherwise the ejection tends to appear with spraying. Higher viscosity ink has been patterned with better characteristics than lower viscosity ink on a nonconductive substrate without surface treatment because higher viscosity has retained the formation of pattern without spreadable phenomenon on a substrate using a direct Electro-Hydrodynamics printing system. Also, higher viscosity ink is better to form a higher aspect ratio of patterning than a lower viscosity ink.