This　study　aims　to　improve　the　fuel　economy　of　extended　range　electric　vehicles　(EREVs)　and　reduce　the　cumulative　battery　workload.　Energy　management　strategy　(EMS)　of　EREVs　has　a　significant　impact　on　improving　the　energy　efficiency,　prolonging　the　service　life　of　batteries,　and　reducing　the　fuel　consumption.　To　the　best　knowledge　of　the　authors,　most　of　existing　studies　are　aimed　at　optimizing　fuel　economy,　but　few　researches　have　taken　the　service　life　of　the　battery　into　account　while　improving　fuel　economy.　Our　study　reflects　the　power　fluctuation　range　of　the　battery　from　the　perspective　of　the　battery　current,　and　also　further　analyzes　it　from　the　perspective　of　the　battery　energy　flow.　On　the　premise　of　meeting　the　vehicle　power　requirement,　matrix　calculation　studies　are　carried　out　on　the　transmission　ratio　and　the　key　parameters　of　EMS　in　the　cooperative　operation　mode　of　hybrid　energy　storage　system　(HESS)　based　on　regular　EMS　and　auxiliary　power　unit　(APU)　based　on　equivalent　fuel　consumption　minimum　strategy　(ECMS).　Via　Simulink　software,　the　corresponding　vehicle　EMS　model　is　developed,　and　the　joint　simulation　platform　of　AVL　Cruise　and　Simulink　is　constructed　to　verify　the　effectiveness　of　the　proposed　EMS.　In　order　to　further　tap　the　energy-saving　potential　of　the　proposed　strategy　based　on　HESS,　the　multi-island　genetic　algorithm　is　adopted.　Under　WLTP　working　condition,　the　global　optimization　is　conducted　with　the　objectives　of　minimizing　the　equivalent　fuel　consumption　and　the　cumulative　ampere-hour　through　the　battery　when　the　vehicle　adopts　HESS　and　APU　&　ECMS　operate　in　concert　operation　mode.　The　correlation　analysis　of　the　optimization　variables　is　performed.　The　results　show　that　the　fuel　economy　of　the　optimized　operation　mode　under　WLTP　condition　is　increased　by　4.49　%,　and　the　cumulative　ampere-hour　through　the　battery　is　reduced　by　11.37　%.