The invention belongs to the field of polymer-based composite paint, and particularly relates to graphene-based waterborne paint and a preparation method thereof. The technical purpose to be achievedis to provide the waterborne polyurethane paint which is good in ductility, high in toughness and good in adhesion force and hardness. By means of molecular structure design, after isophorone diisocyanate (IPDI) is used for isocyan acidification of hydroxyl functional groups on the surface of GO, IPDI is grafted on the surface of GO, then IPDI-grafted graphene oxide reacts with hydroxyl on PCDL through an in-situ polymerization, then chemical bonding of GO and PCDL is achieved, and the dispersion problem and the interface problem of GO in the polymer paint are completely solved. The prepared graphene/polycarbonate diol (GO/PCDL) composite paint has excellent performance of waterborne polyurethane and antistatic property, and can be widely applied to the fields of electronic and electric appliances, functional paint and the like.