Heat　storage　is　a　critical　measure　to　realize　the　utilization　of　waste　heat　and　to　enhance　the　heating　capacity　of　the　medium　-deep　U　-type　borehole　heat　exchanger　(MDUBHE)　system.　However,　the　effects　of　heat　storage　on　the　operation　of　the　MDUBHE　system　remain　unclear.　The　effects　of　heat　storage　measures　on　the　building　and　the　environment　have　not　been　assessed.　In　this　paper,　the　effects　of　heat　storage　measures　on　system　performance　are　revealed　and　assessed　using　the　numerical　heat　transfer　model.　The　results　show　that　heat　storage　measures　are　particularly　necessary　in　severe　cold　regions　of　China.　The　minimum　value　of　the　storage　inlet　temperature　in　this　study　should　be　more　than　42.25　C-degrees,　and　the　flow　rate　is　recommended　at　no　more　than　15　kg/s.　Although　increasing　the　inlet　temperature　of　heat　storage　enhances　the　MDUBHE　system＇s　heating　performance,　the　storage　system＇s　energy　and　exergy　efficiencies　are　attenuated.　Heat　is　mainly　stored　in　the　underground　region　within　6　m　from　the　MDUBHE　and　at　a　depth　of　up　to　2000　m,　and　the　shape　of　the　thermal　plume　is　an　inverted　funnel.　After　adopting　heat　storage　measures,　the　heating　area　supplied　to　buildings　by　the　MDUBHE　system　increases,　and　reduces　environmental　pollution.　Compared　with　the　no　heat　storage　measure,　the　heating　area　of　the　MDUBHE　system　is　increased　by　6770　m(2)　when　the　storage　inlet　temperature　is　80(degrees)　C,　and　the　corresponding　solar　collector　area　needs　to　be　756.1　m(2).　When　T-in(s)　increases　from　45　C　to　80(degrees)　C,　the　reduction　of　CO2　emissions　increases　by　12.43　tons,　21.05　tons,　38.26　tons,　55.41　tons,　and　72.50　tons,　respectively.　This　study　could　promote　the　application　of　the　MDUBHE　system　and　the　heat　storage　system　in　severe　cold　regions.