To　offer　a　new　method　which　can　forecast　and　analyze　performance　of　an　auxiliary　hybrid　electric　vehicle,　a　computer　simulation　model　and　its　controller　were　developed　in　the　system　simulation　software　Matlab/Simulink　environment.　The　bench　test　results　of　key　components　of　the　hybrid　powertrain　were　treated　as　reliable　reference　in　the　modeling.　By　using　those　models,　the　vehicle　distance　for　specific　drive　cycle　was　simulated　and　analyzed.　A　comparison　was　made　when　engine　is　on　and　when　engine　is　off.　The　results　indicate　the　simulation　model　is　in　accordance　with　the　specific　drive　cycle　accurately　so　that　the　simulation　model　is　effective.　This　study　is　helpful　to　the　design　of　an　auxiliary　hybrid　electric　vehicle　and　the　prediction　of　its　performance.