A　virtual　material　model　of　joint　interfaces　was　established　based　on　the　Hertz　contact　theory　and　fractal　theory,　this　model　was　improved　by　considering　the　influence　of　the　elastic-plastic　deformation　of　asperities　and　ameliorating　the　calculation　methods　of　the　elastic　modulus.　The　simulation　results　of　elastic-plastic　considered　and　elastic-plastic　unconsidered　were　compared,　moreover,　the　finite　element　simulation　results　and　experimental　results　were　compared　to　fully　explain　the　necessity　of　considering　the　influence　of　the　elastic-plastic　deformation　and　the　the　correctness　of　the　method　to　calculate　the　elastic　modulus.　The　research　suggested　that　under　a　same　load　the　elastic　modulus　of　the　model　considering　the　influence　of　the　elastic-plastic　deformation　was　slightly　larger　than　the　un　considering　one,　which　means　it　could　describe　the　characteristics　of　joint　interfaces　more　accurately.