Energy　consumption　and　pollutant　emissions　from　buildings　have　caused　serious　impacts　on　the　environment.　Currently,　research　on　building　environmental　costs　is　quite　insufficient.　Based　on　life　cycle　inventory　of　building　materials,　fossil　fuel　and　electricity　power,　a　calculating　model　for　environmental　costs　during　different　stages　is　presented.　A　single-objective　optimization　model　is　generated　by　converting　environmental　impact　into　environmental　cost,　with　the　same　unit　with　direct　cost.　Two　residential　buildings,　one　located　in　Beijing　and　another　in　Xiamen,　China,　are　taken　as　the　case　studies　and　analyzed　to　test　the　proposed　model.　Moreover,　data　uncertainty　and　sensitivity　analysis　of　key　parameters,　including　the　discount　rate　and　the　unit　virtual　abatement　costs　of　pollutants,　are　also　conducted.　The　analysis　results　show　that　the　environmental　cost　accounts　for　about　16%　of　direct　cost.　The　environmental　degradation　cost　accounts　for　about　70%　of　the　total　environmental　cost.　According　to　the　probabilistic　uncertainty　analysis　results,　the　coefficient　of　variation　of　material　production　stage　is　the　largest.　The　sensitivity　analysis　results　indicate　that　the　unit　virtual　abatement　cost　of　CO2　has　the　largest　influence　on　the　final　environmental　cost.