As the electric car and robot industries grow, the importance of the magnet which is the major part of the electric motors has come to the worldwide. At the same time, complex-shaped magnetic components with miniaturization can possibly be required in the market. For this reason, the magnetic powder injection molding process can be a good solution for developing the hard magnetic part in response to the market demands. The magnetic properties of the molded part are greatly influenced by the orientation distribution of the magnetic particles in the molded composite part. In particular, to fabricate the anisotropic magnet with injection molding process, the external magnetic field is applied to the mold cavity for aligning the particle orientation in one direction. The orientation of the magnetic suspension in a polymeric liquid is not only affected by the filling conditions but also by the external magnetic field conditions. Therefore, it is important to develop the analytic and empirical models to predict the magneto-rheological behaviors and consequent particle orientation state during the magnetic-induced injection molding. In this research, a magnetic particle orientation model was developed to predict the orientation of the magnetic particles by extending the mathematical work of Jeffery. For the rheological behaviors, a modified rheological model in consideration of the mold flow behaviors with the external magnetic field was developed by combining Shliomis model and the empirical viscosity model. Taking it a step further, the effect of the induced magnetic field during the filling stage was analyzed with the finite element simulation.