The　efficiency　improvement　of　Hybrid　Electric　Vehicle　(HEV)　is　strongly　dependent　on　the　system-level　control　of　the　power　flow　in　both　the　mechanical　and　the　electrical　paths　of　the　vehicle.　This　is　realized　by　the　HEV　control　strategy.　In　this　paper,　a　control　strategy　is　proposed　for　a　medium　sized　Series　Hybrid　Electric　Vehicle　(SHEV)　designed　for　campus　and　gymnasium.　The　control　strategy　is　composed　of　two　parts:　constant　SOC　control　and　driving　range　optimization.　In　constant　SOC　control,　fuzzy　logic　is　used　to　regulate　the　power　flow　and　maintain　the　SOC　of　batteries　always　at　a　high　level.　Fuel　economy　and　emissions　are　also　considered　by　the　controller.　Both　off-line　and　real-time　simulations　are　performed　and　the　results　verify　the　design　idea.　In　driving　range　optimization,　Ant　Colony　Algorithm　(ACA)　is　used　to　find　the　appropriate　power　sequence　of　Auxiliary　Power　Unit　(APU).　By　comparing　to　thermostat　control　strategy,　with　the　same　fuel　consumption　the　vehicle　after　optimization　may　have　longer　driving　range.　©2010　IEEE.