In this work, an experiment on furnace thermal sintering with printed silver (Ag) nanoparticle ink was carried out. The Ag nanoparticle ink employed in this study has a particle size of around 50 nm and particles constitute 34 wt% of the ink. The Ag nanoparticle ink was printed by inkjet printing. A thermal sintering process in a furnace was conducted at temperatures of 150, 200, and 250 degrees C for 20 to 3000 seconds. After sintering, electrical conductivities and cross-sectional images were measured. The specific resistance and the cross-sectional area of the sintered ink decrease as the sintering temperature increases. The SEM images indicate that surface premelting caused sintering below the melting temperature of silver, 960 degrees C, which increased neck growth and lowered the electrical resistance. Lastly, the minimum specific resistance of 7.08 microOmgega x cm was obtained after sintering for 3000 s at 250 degrees C. This specific resistance value was 4.4 times larger than that of bulk silver.