Powder injection molding (PIM) is one of the important manufacturing technologies to mass-produce near net-shape metallic or ceramic components at a low cost. This technology combines conventional plastic injection molding and powder metallurgy to realize high speed manufacturing of complex geometries with various materials such as metal and ceramic.Magnetic components such as permanent magnets in an electric motor and motor cores made of a soft magnet can also be produced by PIM cost effectively. During magnetic field assisted powder injection molding, anisotropic magnetic particles rotate to align their direction of anisotropy toward externally given magnetic field. The orientation of magnetic particle is mainly affected by flow-particle interaction, particle-external magnetic field interaction and particle-particle magnetic interaction. An analytic orientation model has been developed by extending the mathematical work of Jeffery for the case of magnetic particles. The developed model matched well the result of direct simulation, while it took much less time for computation. These developed models can be efficiently employed to design an optimum process for manufacturing of magnetic component by powder injection molding.