A　novel　dual-cylinder　rotary　compressor　was　designed　to　improve　the　indoor　space　utilization,　and　it　was　used　to　drive　a　parallel-loop　exhaust　air　heat　pump　(PEAHP)　which　integrates　the　functions　of　heating,　cooling,　ventilation　and　heat　recovery.　The　operation　characteristics　of　the　system　in　different　compressor　frequencies　and　different　fresh-air-to-return-air　ratios　(FRRs)　were　studied　and　analyzed　experimentally.　Through　the　simulation　of　the　ultra-low　energy　buildings　(ULEBs)　in　12　cold　zone　cities,　the　hourly　(8760　h)　building　thermal　loads　in　the　whole　year　are　calculated.　On　the　basis　of　the　matching　of　the　hourly　system　working　characteristics　and　the　thermal　loads　of　ULEB,　the　energy　efficient　working　strategy　is　proposed.　Finally,　the　applicability　and　energy　consumption　of　the　PEAHP　system　applying　in　ULEBs　were　analyzed.　The　results　show　that,　the　system　heating/　cooling　capacity　and　COP　can　be　considerably　improved　by　increasing　return　air　volume　flow　rate.　In　winter,　under　the　working　condition　of　50　Hz-FRR　1:1,　the　peak　heating　capacity　and　COP　are　8.94　kW　and　9.63,　respectively,　which　are　77.38%　and　64.05%　higher　than　those　when　FRR　is　1:0.　In　summer,　when　the　outdoor　temperature　ranges　from　26　?to　40　?,　the　system　temperature　effectiveness　is　higher　than　1　in　all　working　modes.　The　PEAHP　system　has　great　applicability　for　ULEBs　in　cold　zone　of　China　during　winter,　and　the　system　can　meet　the　year-round　use　demands　of　the　ULEBs　in　Taiyuan,　Dalian,　Lanzhou,　Yinchuan　and　Lhasa,　with　the　unsatisfied　heating/cooling　time　ratio　of　1.61%,　0.09%,　0.006%,　2.45%　and　0.02%,　respectively.