As screen printing is changed by automation recently, could print more exactly. However, must suffer great many trial and error to have still gotten perfect result. By the way, at this step, fair time and money should be invested. Therefore, if search for optimum condition in early time visualizing screen printing process using simulator program before progress printing, is judged that may be correct and gets printing result efficiently. In this paper, searched optimum printing speed and ink viscosity using FLOW-3D program. Also, the result could confirm truth that is agreeing almost with experiment contents. Through this, is thought that may expect extension of screen printing wide application that vivify advantage of screen print if use simulation program.