The　flexural　vibration　deformation　and　vibration　radiation　noise　of　piezoelectric　vibrator　were　researched.　The　vibration　equations　were　built　to　deduce　the　flexural　vibration　deformation　functions.　Then,　the　simplified　vibration　model　of　piezoelectric　vibrator　was　introduced　using　vibration　theories　of　micro-plane　piston.　Also,　theoretical　equation　of　sound　pressure　in　close　noise　field　and　noise　contribution　equation　of　fluid　in　pump　were　deduced.　Finally,　with　comparison　of　the　theoretical　calculation　and　experimental　testing,　the　results　show　that　the　theoretical　noise　level　of　pump　is　45　dB　and　the　actual　noise　level　is　37　dB,　when　the　input　frequency　is　50　Hz.　Under　this　frequency,　the　fluid　in　the　pump　exerts　great　influence　on　the　pump　noise,　and　the　relative　error　between　the　testing　value　and　theoretical　calculation　is　21.6%.　The　theoretical　noise　level　is　61　dB　and　the　actual　noise　level　is　62　dB,　when　the　input　frequency　is　120　Hz.　In　this　case,　fluid　exerts　little　influence　on　the　pump　noise,　and　the　relative　error　between　the　testing　value　and　theoretical　calculation　is　1.6%.　It　is　concluded　that　contribution　quantities　of　piezoelectric　vibrator　and　fluid　in　pump　under　different　frequencies　are　obtained,　which　proves　that　the　theory　introduced　by　this　research　agrees　with　the　experimental　results　well.