The invention discloses a water-based polyurethane primer for cabin interior decoration. The water-based polyurethane primer is bicomponent water-based polyurethane enamel paint, wherein a component Ais prepared from the ingredients: a PUA emulsion, pigments, functional fillers, a wetting dispersant, a substrate wetting agent, a rheological agent, an antifoamer and a thickener. A component B is prepared from isocyanate and alcohol ether solvents. The researched and developed water-based polyurethane primer has the characteristics of being low in toxicity, low in pollution, good in flame retardance and flexibility, good in adhesion, good in corrosion prevention and free of adverse effect on solvent-sensitive workpieces such as organic glass, plastics and composite materials. Verified by cabin interior coating experiments, the water-based polyurethane primer can completely be popularized to a large scale such as aircraft internal cabins, automobile internal cabins and locomotive internal cabins and has considerable use and economic values.