The　finite　element　model　of　the　bend　pipes　conveying　fluid　is　established　to　explore　the　dynamics　of　the　fluid-filled　pipe　in　a　spacecraft　energy　supply　system.　Modal　analysis　of　the　fluid-filled　pipe　is　executed　to　study　the　effects　of　thickness,　diameter　and　bending　angle　of　the　pipes　on　the　natural　frequency.　On　the　other　hand,　a　length　of　pipe　conveying　fluid　in　a　proton　exchange　membrane　fuel　cell　system　is　selected　to　analyze　the　impact　of　the　unsteady　flow　of　pipes　fluid　on　its　dynamic　properties.　The　influences　of　the　installed　position　of　valve　and　pipe＇s　thickness　on　the　value　of　pipe＇s　displacement　and　stress　are　studied.　Numerical　results　show　that　the　fluid-structure　interaction　(FSI)　causes　a　reduction　of　the　natural　frequency　of　pipes.　With　increasing　pipe　thickness,　the　pipe　natural　frequency　increases.　The　pipe　diameter　and　bending　angle　have　a　less　important　effect　on　the　low　order　natural　frequency　of　pipes,　while　the　effect　should　be　taken　into　account　on　the　high　natural　frequency.　The　smaller　the　material　stiffness　is,　the　greater　the　influence　on　the　FSI　becomes.　Meanwhile,　the　unsteady　flow　of　the　fluid　can　result　in　jumping　of　the　wall　displacement　and　stress.　The　installation　position　of　valve　has　little　effect　on　the　amplitude　of　the　pipe＇s　displacement　and　stress;　however,　the　stress　position　changes　with　its　extreme.　With　increasing　pipe　thickness,　the　amplitude　of　pipe　displacement　and　stress　decreases.　©,　2015,　Beijing　University　of　Technology.　All　right　reserved.