This paper presents full coupling simulation of a whole micropump: three-dimensional (3-D) numerical simulations are carried out with consideration of interaction between electro mechanics and solid mechanics, solid mechanics and fluid mechanics. The simulation of a membrane micropump with diameter 6 mm, driven by PZT disc is implemented using CFD-ACE+, the commercial software from CFDR. A series of transient simulations are carried out under the excitation of Sine-wave voltage 70V and at the frequencies 8, 50, 100, 200 and 500 Hz respectively. The deflections of membrane, the detailed fluid fields and the pump performance curves are shown. Computational effort required for the case studies is discussed. The present simulation shows that computational CPU time increases with the increasing electrical driving frequency. The 3-D coupling simulation is acceptable for design and analysis in the lower actuating frequency region, i.e. fC 50 Hz for the present micropump model. In higher frequency region, extensive CPU time is required.