The work aims to investigate the effect of kaolin added into varnish on the printability of water-based ink. Kaolin was used to prepare diluent and then different contents of diluent were applied to compound 3 kinds of varnish which were mixed with 5 different types of colorants to prepare ink. Eventually, the printability of these inks was investigated from the aspects of slip resistance, viscosity, pH value, bubbling, deposit, fineness and color rendering effect. The addition of diluent to varnish slightly reduced the slip resistance of water-based anti-slip ink, but did not affect the pH value, fineness and color rendering effect of ink. However, the ink sample 1 with large content of diluent caused an obvious deposit, which might affect the printability. The water-based ink prepared with 10%-12% varnish can meet the printing requirements, which has certain reference significance for the preparation and application range of water-based ink.