The fraction of hydrogen (H2) in the blast furnace (BF) shaft gas containing a notable portion of nitrogen (N2) is expected to increase. For more efficient control of the BF, it is therefore desirable to conduct more rigorous studies on gaseous reduction of iron ores especially in H2-N2 atmosphere. In this paper, an unreacted shrinking core model (USCM) with multicomponent gas diffusion for iron ore reduction in H2-N2 atmosphere is developed. The resultant nonlinear equations are solved using the 4th order Runge-Kutta method. The present model and the original USCM are compared based on a series of pertinent experimental data.