The threedimensional unsteady flow simulation of a centrifugal pump was carried out by solving the unsteady NavierStokes equations.Dipole sources were extracted in the calculation. The unsteady characteristic of flow field and the major noise source were analyzed on the basis of computational fluid dynamies results.The response solution on the boundary surface was finally calculated by using boundary element method in two cases, in which the vibration is neglected or considered. By comparison,it appears that the case of considering vibration is more reasonable.The levet of dipole sources noise radiation in the pump was solved successively based on the results of vibrationacoustic coupled calculation.