Cement　mortar　is　an　important　part　of　building　material　and　a　typical　cement　matrix　composite　material.　In　current　work,　the　mechanical　properties　and　failure　mechanism　of　cement　mortar　under　static　compression　are　studied　by　using　the　Base　Force　Element　Method　(BFEM).　The　static　compression　damage　program　of　cement　mortar　is　compiled　grounded　on　the　BFEM　of　the　potential　energy　principle.　An　elastic　polyline　damage　constitutive　model　is　put　forward　to　express　the　meso-damage　and　evolution　process　of　cement　mortar.　A　2D　random　circular　aggregate　model　of　cement　mortar　was　established.　The　numerical　simulation　of　the　uniaxial　static　compression　is　carried　out,　the　stress-strain　curve,　damage　process,　and　damage　model　are　obtained.　The　strength　of　the　interfacial　transition　zone　and　the　failure　process　of　hardened　cement　mortar　were　discussed.　A　mesoscopic　equivalent　model　is　proposed　to　analyze　the　mechanical　properties　of　cement　mortar　by　considering　the　effect　of　initial　porosity.