Purpose　Based　on　the　base　force　element　method,　a　two-dimensional　random　circle　aggregate　model　with　Monte　Carlo　principle　is　proposed　to　carry　out　research　on　softening　curve　in　meso-level.　Design/methodology/approach　The　meso-level　structure　of　recycled　concrete　is　considered　as　the　five-phase　materials　composed　of　aggregate,　old　interfacial　transition　zone,　old　mortar,　new　interfacial　transition　zone　and　new　mortar.　A　multi-polyline　damage　model　is　adopted　to　describe　the　nonlinear　mechanical　behavior　of　recycled　concrete　material.　The　destruction　state　of　the　element　is　determined　by　the　first　strength　theory.　The　research　studies　on　damage　process　of　recycled　concrete　under　the　loading　conditions　of　uniaxial　tension　were　established　using　the　base　force　element　method.　Findings　The　softening　curves　of　recycled　concrete　are　obtained,　which　are　in　good　agreement　with　experiment　results.　Simulation　results　show　that　the　macroscopic　mechanical　properties　and　failure　mechanism　can　analyze　more　reasonably　from　mesoscopic　structure.　Besides　that,　it　can　be　investigated　from　the　numerical　results　of　the　size　effect　in　recycled　concrete　through　the　mesoscopic　heterogeneity.　Furthermore,　the　form　of　aggregate　distribution　has　influence　on　the　crack　path　but　little　effect　on　the　tensile　strength　of　recycled　concrete.　Originality/value　The　results　show　that　the　base　force　element　method　has　been　successfully　applied　to　the　study　of　softening　curve　of　recycled　concrete　under　uniaxial　tension.