Abstract: Unsteady flow equations for centrifuge are solved on a staggered grid by a finite volume method in this paper. The transient process that the axial flow in the centrifuge is established under a steady thermal driving is revealed. It can be concluded that the influence which causes the perturbing fluid is different at the beginning and the end in the processing. The flow is caused by the imbalance of temperature turns to be caused by the imbalance of pressure. The result shows that the numerical simulation is effective in the study in the unsteady fluid in a centrifuge.