In　this　study,　three　typical　limestones,　including　Tavel　limestone,　Indiana　limestone,　and　Lixhe　chalk,　were　selected　from　a　large　number　of　porous　limestones.　These　limestones　with　different　porosities　have　been　largely　studied　in　previous　experimental　investigations　because　of　the　complexity　of　mechanical　behavior.　According　to　previous　experimental　studies,　porous　limestones　present　two　basic　plastic　mechanisms:　plastic　shear　as　a　response　at　low　confining　pressures　and　plastic　pore　collapse　at　high　confining　pressures.　In　related　to　the　plastic　mechanisms,　two　types　of　plastic　volumetric　deformation　are　revealed:　plastic　compaction　induced　by　pore　collapse,　and　plastic　dilatancy　by　plastic　shearing.　In　this　paper,　a　micromechanics-based　plastic　model　is　extended　to　describe　the　elastoplastic　behavior　of　porous　limestones.　The　plastic　criterion　of　porous　rock　is　explicitly　dependent　on　the　porosity　in　addition　to　being　directly　based　on　the　relevant　mechanical　properties　of　solid　matrix　at　the　microscopic　scale.　An　additional　plastic　hardening　law　for　the　solid　matrix　is　proposed,　in　which　two　plastic　deformation　mechanisms　are　considered　in　hardening　law　of　the　solid　matrix,　including　hardening　effect　caused　by　the　local　equivalent　plastic　deformation　and　weakening　effect　caused　by　the　increase　in　porosity.　Three　typical　porous　limestones　with　different　porosity　are　selected　to　validate　the　proposed　model　on　both　hydrostatic　and　triaxial　compression　tests.　By　comparing　numerical　predictions　and　experimental　data,　it　is　shown　that　the　presented　model　can　correctly　describe　the　mechanical　behavior　of　porous　rocks.