Abstract: Computational Fluid Dynamics (CFD) method was adopted to simulate the 2D symmetrical feed-jet flow-field in Iguacu gas centrifuge, in order to study the influence of feed-jet to counter-current. The data acquired from calculation were used to modify the feed boundary condition in counter-current calculation, and the stream lines distribution was got considering the effect of the feed-jet. Finite volume method and 2-order implicit scheme were adopted to solve Navier-Stokes (N-S) equations in cylinder coordinates to simulate the feed-jet flow. Finite difference method was used to solve centrifuge fluid dynamics equations. The results indicate that the feed-jet flow affects the counter-current observably, the results of feed-jet flow simulation can be used to modify the conditions to calculate the counter-current in the real centrifuge.