A numerical scheme has been developed to predict the flow induced fiber orientation for the filling stage of injection molding process with complex mold geometry. Experiments were performed to validate the numerical scheme for various geometries. The flow analysis was performed by employing finite element/control volume method and particle tracing method was newly adopted to predict the fiber orientation. Both numerical simulations and experimental observations demonstrated that the fibers in diverging flow are oriented perpendicular to the flow while the fibers in converging flow, near the weldlines and side walls, tend to orient parallel to the flow. It was confirmed that there exists the skin-core structure which indicates two different layers through the gap width. The reason why the numerically predicted skin layer was thicker than experimentally observed one is probably due mainly to the nonuniformity of fiber concentration caused by the restriction of fiber motion at the walls, the fountain flow effect, the effect of slip velocity at the wall boundaries, and the interaction coefficient, which could not be fully accounted for in the numerical simulation. There were consistent agreements between the experimental observations and the numerically predicted results for various flows including the case of three dimensional thin mold.