Acrylic-polyurethane (PUA) hybrid aqueous emulsion with core-shell structure was prepared via semibatch emulsion copolymerization of the acrylate monomers (AC) in the presence of a commercial polyurethane dispersion as seeds.The core-shell structure of the emulsion was observed by TEM.The particle size and distribution of the emulsion was found to vary drastically with the core-shell ratio.The thermal response properties of emulsion films were measured by DSC,and the results indicated the good compatibility between PA and PU moieties in PUA hybrids.The chemical structures of emulsion films were studied by FTIR,and the surface properties were tested by contact angle measurement.The results supported the idea that the surface of the cast films was rich in polyurethane component.The water resistance of the cast films became better by increasing the AC fraction.The rheological properties of the latex and its utilization as a binder for aqueous pigment inks of digital inkjet printing were thoroughly investigated,indicating that the prepared hybrid emulsion could be used safely for aqueous pigment inks of digital ink jet printing.