In this work, rheological property and flash light sintering characteristic of Cu/Ag hybrid-ink were investigated for multi-layered printed circuit board application. Firstly, Cu/Ag hybrid-ink was fabricated with various composition of epoxy content, the fabricated Cu/Ag hybrid-inks were printed to the polyimide (PI) substrates to observe printing characteristics of pattern and via-hole area according to the rheological property of ink. Then, the printed Cu/Ag hybrid-inks were sintered with various flash light sintering condition to observe flash light sintering characteristics. As a result, the optimally fabricated ink showed good printability of pattern and via-hole area, and optimized multi-pulse flash light sintering case exhibited low resistance (0.18 Ohm/cm) and high adhesion strength (5B).