Microbial-induced　carbonate　precipitation　(MICP)　technique　has　the　potential　to　be　an　eco-friendly　and　sustainable　solution　for　engineering　problems.　Despite　the　extensive　amount　of　research　that　has　been　conducted　recently　on　the　MICP　technique,　there　are　few　studies　on　the　constitutive　model　of　MICP-treated　specimens.　In　this　study,　the　statistical　damage　constitutive　model　of　MICP-treated　specimens　was　established　based　on　the　statistical　theory　and　damage　mechanics　theory.　The　proposed　model　assumed　that　the　microelement　strength　of　biocemented　sand　follows　the　lognormal　distribution　and　the　Drucker-Prager　criterion.　The　parameters　S0　and　F0　in　the　constitutive　model　were　determined,　and　their　physical　significance　was　then　discussed.　The　reasonableness　of　the　proposed　model　was　verified　by　comparing　the　theoretical　results　and　the　experimental　results.　The　evolution　of　the　damage　variable　(D),　parameter　S0,　and　parameter　F0　with　different　calcium　carbonate　content　(CCC)　was　analyzed.　The　statistical　damage　model　based　on　the　lognormal　distribution　was　then　compared　with　that　based　on　the　Weibull　distribution.　The　results　show　that　the　parameter　F0　and　S0　can　reflect　the　limiting　strength　and　brittleness　of　MICP-treated　specimens..　The　specimens　with　higher　cementation　tend　to　have　a　higher　accelerated　damage　rate.　The　damage　variables　eventually　reach　a　stable　value　as　the　axial　deformation　increases.　The　proposed　model　can　reflect　the　strain　softening　and　strain　hardening　phenomena　well,　which　can　also　represent　the　shear　expansion　and　shear　contraction　characteristics　of　the　volume　strain　curve.　Overall,　the　research　in　this　study　can　provide　some　theoretical　support　for　the　engineering　application　of　MICP-treated　specimens.