Electrical　energy　of　low　voltage　is　typically　required　to　be　boosted　through　a　high　voltage　gain　DC-DC　converter　to　match　the　bus　voltage.　A　high　gain　step-up　Cuk　converter　is　proposed　in　this　paper.　By　combining　coupled-inductor　and　diode-capacitor　units,　the　step-up　gain　of　the　proposed　converter　was　further　improved,　and　the　voltage　spike　of　the　transistor　caused　by　the　leakage　inductance　was　effectively　suppressed　by　the　introduced　units.　In　order　to　improve　the　dynamic　performance　and　the　anti-disturbance　ability　of　the　proposed　converter,　an　improved　fuzzy　control　method　based　on　Takagi-Sugeno-Kang　(TSK)　fuzzy　control　technique　was　proposed,　whose　output　scale　factor　is　dynamically　changed,　and　it　possesses　the　characteristics　of　strong　robustness,　fewer　fuzzy　rules,　less　calculation,　and　simpler　control.　The　operating　principles,　operating　characteristics　and　the　proposed　control　strategy　of　the　converter　were　analyzed　in　detail.　The　simulation　was　carried　out　in　this　paper　and　an　experimental　prototype　with　input　of　36　V-70　V　and　output　of　400　V/400　W　was　built.　The　simulation　and　experimental　results　show　that　the　converter　voltage　gain　can　be　effectively　improved　by　designing　the　appropriate　turns　ratio.　The　efficiency　is　up　to　96.4%　under　the　48　V　input.　Compared　with　the　traditional　PI　control,　the　proposed　fuzzy　control　strategy　can　suppress　the　disturbance　more　effectively　when　the　input　voltage　was　stepped　between　36　V　and　70　V　and　load　was　stepped　between　0.05　A　and　1　A　respectively,　which　improves　the　dynamic　performance　of　the　proposed　converter.　©　2021,　Harbin　University　of　Science　and　Technology　Publication.　All　right　reserved.