Inspired　by　the　principle　of　cascade　energy　utilization,　the　concept　of　cascade-heating　is　introduced,　and　five　layouts　of　cascade-heating　high　temperature　heat　pump　(HTHP)　systems　are　proposed　and　optimized　to　utilize　the　waste　heat.　The　energy　consumption,　carbon　and　pollutant　emissions,　life　cycle　cost　(LCC)　and　payback　period　(PBP)　models　are　established.　Meanwhile,　detailed　comparisons　are　made　with　conventional　HTHPs　and　boilers.　The　results　indicate　it　is　more　positive　for　cascade-heating　HTHPs　in　terms　of　energy　consumption,　carbon　and　pollutant　emissions,　LCC　and　PBP.　The　primary　energy　consumption　of　cascade-heating　water　cooled　saturated　suction　system　(CWSAS)　is　declined　by　1.8–22.8%　and　3.4–19.2%　in　contrast　to　conventional　HTHPs　and　traditional　boilers,　respectively.　The　life　cycle　carbon　emissions　of　CWSAS　are　reduced　by　1.7–6.1%　and　76.5%　compared　to　conventional　HTHPs　and　electric　boiler.　The　pollutant　emissions　can　also　be　prominently　declined　by　adopting　cascade-heating　HTHPs.　For　life　cycle　economic　performance,　LCC　of　cascade-heating　flash　tank　superheated　suction　system　(CFSUS)　can　be　reduced　by　4.5–18.3%　compared　with　traditional　HTHPs.　Furthermore,　PBP　of　CFSUS　is　the　lowest　of　3.1　years,　and　15.4–65.9%　shorter　than　traditional　HTHPs.　CWSAS　is　the　most　recommended　configuration　on　account　of　its　remarkable　overall　energy,　environment　and　economic　performances.　©　2022