Renewable　nacre-like　heparin　(HEP)/layered　double　hydroxide　(LDH)　ultrathin　films　were　first　fabricated　via　a　bottom-up　layer　by　layer　(LBL)　deposition　technique,　which　simultaneously　showed　largely　enhanced　mechanical　properties　and　good　blood　compatibility.　The　results　of　UV-vis,　FTIR,　XRD　and　SEM　analysis　indicate　that　the　HEP/LDH　ultrathin　films　stacked　densely　together　to　form　a　well-defined　brick-and-mortar　structure.　A　strong　electrostatic　and　hydrogen　bond　network　at　the　organic　inorganic　interface　allowed　the　modulus　of　the　film　reach　ca.　23　GPa,　which　was　remarkably　enhanced　compared　to　previously　reported　polymer　LDH　hybrid　films.　Due　to　the　interlamellar　heparin,　the　(HEP/LDH)　film　may　prove　to　be　beneficial　for　new　medical　applications　or　as　a　replacement　for　conventional　petroleum　based　plastics.