In　this　paper,　the　elastoplastic　and　creep　constitutive　behaviors　of　sintered　silver　with　varying　amounts　of　nickel-modified　multiwall　carbon　nanotubes　are　studied　through　a　systematic　investigation　of　the　nanoindentation　test.　Elastoplastic　stress-strain　curves　for　the　sintered　silver　with　different　additive　content　are　obtained　based　on　reverse　analysis.　The　addition　of　nickel-modified　multiwall　carbon　nanotubes　reduced　the　yielding　stress　from　110.68　MPa　to　61.61　MPa　and　generally　increased　the　strain-hardening　exponent　from　0.26　to　0.41.　The　initial　and　steady-state　creep　stress　exponent　remained　almost　unchanged.　However,　the　creep　coefficient　increased　remarkably.　Otherwise,　the　yielding　stress　was　confirmed　to　agree　well　with　the　Hall-Petch　relation,　and　the　hardening　exponent　was　found　to　follow　Morrison＇s　law.　The　creep　exponents　and　creep　coefficients　were　also　obtained　and　shown　to　be　highly　related　to　the　particle　size　and　positively　correlated　with　porosity.　The　creep　regime　at　room　temperature　was　confirmed　to　obey　Sherby＇s　model.　This　investigation　shows　the　effect　of　additive　content　on　sintered　silver.　The　study　given　in　this　paper　could　deepen　the　understanding　of　the　strengthening　effect　of　nickel-modified　multiwall　carbon　nanotubes　on　the　mechanical　performance　of　sintered　silver　at　room　temperature.