This paper disclosed recent novel development in printing circuit on flexible substrate by combining self-assembled polyelectrolytes, inkjet printing of catalyst, and electroless plating of metal. Experimental results indicated that building up zone model would enhance substrate surface uniformity. The results also showed that salt concentration would dramatic change the polyelectrolyte layer property before ink-jet printing of catalyst. Salt ions would balance charges in polyelectrolyte layers and smear the surface. It made the finer diameter of porous hole and significantly increased the adhesion between the ink-jet catalyst and the substrate. Surface uniformity was controlled within ±5%. A high quality circuit fabricated by said ink-jet printing method is presented.