Battery　is　widely　used　as　the　only　energy　storage　system　for　domestic　hybrid　electric　vehicle　(HEV).　Short　battery　life　is　becoming　the　biggest　obstacle　in　the　rapid　development　of　HEV,　adding　ultracapacitor　pack　into　the　HEV　energy　storage　system　can　solve　this　problem.　After　analyzing　the　principles　and　characteristics　of　ultracapacitor,　the　model　of　hybrid　energy　storage　system　(HESS)　had　been　established　in　matlab/simulink,　battery　and　ultracapacitor　was　in　parallel　connection,　joined　with　HESS　control　strategy,　and　also　designed　the　topology　of　the　HESS.　Then　selected　components　and　conducted　matching　parameters　of　the　system.　By　simulating　the　pulse　power　input,　a　single　battery　powered　HEV　had　been　compared　with　a　HESS　supplied　HEV　in　power　supply　capacity.　The　results　showed　that　the　HESS　powered　hybrid　vehicles　can　reduce　high　current　charge　and　discharge　times　of　the　battery,　and　be　able　to　meet　the　power　requirements.　©　2010　IEEE.