The　cylindrical　volute　intake　structure　possesses　some　advantages　including　convenient　processing,　convenient　installation　&　uninstallation　and　high　machining　efficiency.　The　helium　turboexpander　with　this　novel　intake　structure　in　a　superconducting　cryogenic　device　is　investigated　deeply　in　this　study.　Based　on　the　established　mathematical　model　and　the　corresponding　numerical　computation　methods,　the　whole　flow　passage　internal　flow　of　the　helium　turboexpander　is　numerically　simulated.　And　then　the　distribution　characteristics　of　total　pressure,　static　pressure,　static　temperature,　relative　velocity　and　total　enthalpy　in　the　cylindrical　volute,　nozzle,　impeller　and　diffuser　are　explored,　and　loss　mechanism　of　the　internal　flow　is　analyzed.　The　results　indicate　that　the　novel　cylindrical　volute　intake　structure　has　obvious　pre-rotation　effect　on　the　inlet　flow　field　of　the　nozzle,　and　this　intake　structure　has　little　loss.　In　addition,　the　expansion　effect　in　downstream　components　including　nozzle　and　impeller　is　obvious,　and　the　flow　field　changes　uniformly.　The　overall　efficiency　of　the　turboexpander　is　up　to　84.8%,　which　indicates　that　it　is　reasonable　that　the　novel　cylindrical　volute　is　used　as　the　intake　structure　of　turboexpander.