Influencing factors on electric resistance of electrically conductive ink were analyzed. A screen printing process was designed and bar codes were printed on different substrates using electrically conductive ink. The prints were dried and the electric resistance of bar codes of electrically conductive ink was tested, processed and analyzed. The results showed that the bar code resistances of electrically conductive ink change with different screen lines, therefore, bar code printed by electrically conductive ink can be another effective way for package anti-counterfeit printing.