In　view　of　the　characteristics　of　APU　with　the　parameters　discreteness,　the　nonlinearity　and　uncertainty,　a　new　type　speed　control　system　of　APU　based　on　the　theory　of　fuzzy　control　was　developed　in　this　paper,　to　ensure　the　running　of　gasoline　engine　in　APU　to　be　economic　and　with　high　efficiency.　The　structure　and　working　principle　of　the　fuzzy　controller　were　described,　and　the　design　procedure　of　the　fuzzy　controller　was　given　in　detail.　The　experimental　results　show　that　the　step　response　of　the　speed　is　small　in　the　overshoot,　little　in　the　fluctuation　range　and　the　regulation　time.　This　control　system　has　not　only　achieved　the　purpose　of　speed　control　of　APU　but　also　has　good　quality.　The　results　are　validated　by　road　tests,　and　show　that　the　fuzzy　controller　can　guarantee　the　engine　is　running　in　the　economic　region,　while　ensure　the　efficiency　of　generator.　The　desired　purpose　and　effect　of　control　system　can　be　achieved.