Foil　bearings,　featuring　various　advantages　(such　as　high-speed,　good　operation　stability,　low　friction,　long　life,　strong　adaptability,　wide　temperature　range,　and　oil-free),　are　promised　to　have　good　development　prospects　and　application　in　high-speed　centrifugal　machinery.　In　order　to　evaluate　the　actual　performance　of　the　multi-leaf　foil　bearings　and　promote　their　further　application　in　the　high-speed　turbo-machinery,　the　experimental　research　of　multi-leaf　foil　bearings　with　rotor　diameter　of　25　mm　are　conducted　in　this　paper.　The　static　and　transient　tests　of　the　multi-leaf　journal　bearings　with　different　foil　thickness　are　initiated　on　the　journal　bearing　test　rig　to　analyze　their　characteristics,　such　as　the　load-deflection,　bearing　Coulomb　friction,　start-up　and　operating　friction　torque,　which　could　provide　guidance　for　the　structural　parameter　design　and　exploitation　of　the　bearing.　Afterwards,　two　different　bearing　combinations　are　adopted　as　the　supporting　components,　namely　A-type:　multi-leaf　foil　journal　bearing　with　aerostatic　thrust　bearing　and　B-type:　multi-leaf　foil　journal　bearing　with　multi-leaf　foil　thrust　bearing.　They　are　applied　in　the　high-speed　turbo　machinery　with　the　rotor　diameter　of　25　mm　to　assess　the　direct　application　of　the　multi-leaf　foil　bearings　in　high-speed　turbo-machinery.　The　transient　speed-up,　high　speed,　and　speed-down　experiments　of　the　rotor-bearing　system　are　conducted　and　their　transient　characteristics　and　stability　are　compared.　The　experimental　results　indicate　that　the　start-up　(0.6x10-2~1.8x10-2Nm)　and　steady　operation　frictional　torque　(0.25x10-2~0.5x10-2Nm)　of　the　multi-leaf　foil　journal　bearing　is　relative　small;　the　impeller-rotor　system　operates　steadily　and　smoothly　with　good　repeatability,　supported　by　A-type　and　B-type,　the　maximum　rotor　speed　at　about　94krpm　achieved　in　the　tests　is　close　under　the　support　of　A-type　and　B-type.　However,　there　are　smaller　main　frequency　amplitude,　nonsynchronous　amplitude　and　better　rotor　orbit　in　the　transient　processes　with　the　support　of　B-type,　which　indicates　better　stability.　[DOI:　10.1299/jamdsm.2020jamdsm0085]