In　3D　electronic　package　technologies,　through　silicon　via　(TSV)　plays　a　critical　important　role.　TSVs　are　usually　fully　filled　by　electroplating　copper,　namely　TSV-Cu,　which　has　very　different　mechanical　properties　from　bulk　copper.　To　obtain　the　mechanical　properties　of　the　TSV-Cu,　the　Berkovich　nanoindentation　tests　were　conducted,　and　the　Oliver-Pharr　algorithm　and　the　continuous　stiffness　measurement　method　were　used　to　acquire　the　elastic　modulus　and　hardness.　Then　finite　element　modeling　(FEM)　simulations　are　adopted　for　reverse　analysis　of　the　nanoindentation　loading　process　to　determine　the　representative　stress　and　strain　of　the　TSV-Cu　by　comparing　the　maximum　value　of　simulated　load　to　that　of　experimental　load.　The　strain　hardening　exponent　of　the　TSV-Cu　is　determined　by　dimension　functions.　The　yield　strength　of　the　TSV-Cu　is　acquired　by　substituting　the　representative　stress,　the　representative　strain　and　the　strain　hardening　exponent　into　a　power　law　stress-strain　constitution.　Finally,　a　power　law　elastic-plastic　stress-strain　relationship　of　TSV-Cu　is　built.　The　obtained　elastic　modulus　and　hardness　of　the　TSV-Cu　are　155.47　GPa　and　2.47　GPa,　respectively;　the　strain　hardening　exponent　is　0.4892　and　the　yield　strength　is　47.91　MPa.