Inkjet printing is a widespread technology, offering advantages such as high-quality decoration, a continuous process, and the accurate direct reproduction of patterns or pictures. In inkjet printing technology, the dispersion stability of ceramic ink is one of the most important factors. In this study, the dispersion stability of blue CoAl₂O₄ ink for ceramic inkjet printing is systematically investigated. Blue CoAl₂O₄ pigment was synthesized by a solid-state reaction and then milled to less than 300nm in size. In order to investigate the influence of the viscosity on the dispersion stability, two types of CoAl₂O₄ ceramic inks (termed here Blue L and Blue H) were prepared using different volume ratios of ethylene glycol and ethanol. The Blue L and Blue H ink solutions contained cetyltrimethylammonium bromide(CTAB) as a dispersive agent. The viscosity, surface tension and jetting stability of the CoAl₂O₄ ceramic inks were analyzed using a rheometer, a surface tension meter and a dropwatcher. The dispersion stability of the CoAl₂O₄ceramic ink was investigated by a multiple light-scattering method. Blue H, a ceramic ink with higher viscosity, showed much better dispersion stability than the Blue L ceramic ink.