Abstract: To investigate the influence of feed condition on the flow field and separation performance of gas centrifuge, flow field distribution was obtained by numerically solving linearized Navier-Stokes equation with finite difference method, which separation power was calculated based on. Curves of separative power changing with different feed parameters were drawn. The numerical results show that flow field distribution and separative performance have significant difference under different feed conditions. By comparing a large number of calculation results, combined with centrifugal separation theory, analyses were made about the mechanism that different feed factors influence separation performance of the centrifuge. A conclusion was obtained that position, axial velocity disturbance and angular velocity disturbance are main factors that influence flow field. The optimal position and feed angle are existed for the given model according the results. The research shows that the feed flow and mechanism of feed drive need further research.