Water-based polyurethane forms continuous and dense film after fully drying. Ink is lowly absorbed by PU film, affecting drying rate and color reproduction. In order to improve the absorption of ink on PU film, PU/nano alumina compound was prepared by adding nano alumina in PU and stirring at high speed. PU ink absorption coating was got by being coated on the substrate. The influences of different content of nano alumina to transmittance of coating and solid density of color blocks were researched. The influences of soft and hard segment of PU to image resolution and water resistance were also researched. It can be seen that transmittance reduces when content of nano alumina increases. Droplets spread less when using PU of hard segment and image resolution and solid density are also higher. At the same time, water resistance of solid blocks is much better when printed on PU of hard segment.