We have investigated the inkjet-printing of Al 2 O 3 ink on the solid surface. The deposit patterns of nanoparticles from ink droplets were controlled by adding a drying agent to the main ink solvent. This co-solvent ink system creates a circulating flow in the ink droplet during its drying process, resulting in a uniform deposit of nanoparticles from the ink droplet. The study on the spreading of Al 2 O 3 ink droplets on the solid surface was implemented to identify an optimum condition for the inkjet printing of straight lines. With the inkjet-printed straight lines, uniform Al 2 O 3 films were printed by adjusting the line-to-line pitches and investigated by SEM and a surface profiler.