Micropump　is　the　key　component　in　the　micro　total　analytical　system.　The　major　technical　impediment　in　improving　the　performance　of　this　micro-device　lies　in　the　lack　of　understanding　the　physical　phenomena　and　their　interactions　of　electric,　mechanical,　and　fluidic　fields　for　performing　their　intended　functions.　Because　of　the　complexity　of　the　micropump,　the　full　coupled　numerical　analysis　is　extremely　needed.　This　paper　presents　for　the　results　of　such　fully　coupled　simulations.　CFDRC　(R)　was　used　for　the　transient　analysis　of　an　electrostatically　actuated　micropump.　The　results　show　that　the　dynamic　characteristics　of　fluid　in　the　micropump　and　the　vibration　of　flexible　diaphragm　are　highly　interactive　each　other.　The　flow　rectification　of　the　nozzle/diffuser　will　work　only　after　the　pressure　difference　between　the　two　ends　of　valve　have　reached　at　a　critical　value.　In　the　pump　chamber,　the　fluidic　press　distribution　almost　independent　of　the　space　variation.　Due　to　the　increasing　demands　for　accuracy,　the　nonlinear　features　of　viscous　loss　of　the　fluid　can　no　longer　be　neglected　or　simplified,　but　have　to　be　taken　into　account　in　detail.