The purpose of this study was to present the method to choose the optimization machining condition for the wire electric machine. This was completed by examining the ever-changing quality of the material and by improving the function of the wire electric discharge machine. Precision metal mold products and the unmanned wire electric discharge machining system were used and then applied in industrial fields. This experiment uses the wire electric discharge machine with brass wire electrode of 0.25mm. To measure the precision of the machining surface, average values are obtained from 3 samples of measures of center-line average roughness by using a third dimension gauge and a stylus surface roughness gauge. In this experiment, we changed no-node voltage to 7 and 9, pulse-on-time to $6{mu}s,;8{mu}s$ and $10{mu}s$, pulse-off-time to $8{mu}s,;10{mu}s$ and $13{mu}s$, and experimented on wire tension at room temperature by 1000gf, 1200gf, and 1400gf, respectively.