The　interfacial　precipitation　of　reinforced　particles　has　a　critical　influence　on　particle-reinforced　aluminummatrix　composites.　In　this　study,　TiB2　interfacial　precipitation　of　6　wt%　TiB2/Al-10Zn-2.3　Mg-2Cu-0.12Zr　composite　was　studied.　The　results　demonstrate　that　the　TiB2　surface　has　a　considerable　impact　on　precipitation　during　different　states　of　the　composite　preparation　process　(including　heat　treatments).　The　TiB2　surface　acted　as　a　nucleation　site　for　D023-Al3Zr　and　was　wrapped　with　the　T　phase　during　solidification;　a　good　orientation　relationship　existed　between　TiB2　and　D023-Al3Zr:　(0　00　1)TiB2//(1　03)D023-Al3Zr,　(1　01　0)TiB2//(1　05)D023-Al3Zr,　and　[1　21　0]TiB2//[0　1　0]D023-Al3Zr.　After　homogenization　or　solution,　the　TiB2　wall　hindering　solute　atoms　diffused　into　the　matrix,　particularly　for　Mg　and　Cu,　causing　the　T　phase　to　dissolve　incompletely,　and　the　residual　T　phase　on　the　TiB2　surface　transformed　to　the　S　phase　layer　at　a　longer　holding　time.　Additionally,　the　hindering　effect　of　the　TiB2　walls　results　in　the　enhancement　of　the　local　high　solute　atom　concentration　and　provides　a　high　precipitation　driving　force.　Therefore,　the　interfacial　phase,　Mg(Cu2-XZnX),　preferentially　precipitated　at　the　D023-Al3Zr　and　S　phase　interface　during　peak　aging.　In　this　process,　the　periodic　misfit　dislocations　of　the　interface　facilitate　the　diffusion　of　solute　atoms　and　reduce　the　nucleation　energy　barrier,　promoting　interfacial　precipitation.　Eventually,　the　interfacial　precipitates　layer　relieved　the　local　stress　concentration　but　consumed　the　solute　atoms,　which　was　considered　to　be　beneficial　to　plasticity　at　the　cost　of　strength　weakening　to　achieve　excellent　comprehensive　mechanical　properties.