Abstract: A novel method is presented to synthesize Negative Refractive Index Material (NRIM) by incorporating array of metallic wires into the host media such as ferrimagnet-YIG under an external magnetic bias field. The effective electromagnetic properties of the composite medium are calculated analytically based on the effective medium theory. The results show that the effective permittivity and effective permeability of the composite medium are negative simultaneously in C-band frequency region, and therefore indicate the proposed method to synthesize NRIM is feasible.