The magnetic and structural properties of FINEMET [Fe73.5Si13.5B9Nb3Cu1 wt %] amorphous powder were investigated after nitrification and mechanical milling. Fe-based amorphous powder were nitrified and crystallized simultaneously at 550°Cusing by ammonia(NH3) gas. Nitrified powder exhibited iron nitride phase such as γ′-Fe4N, Fe3N and α″-Fe16N2. Nitrified particles were more brittle than raw particles. As a result, nanometer sized nitride powder were fabricated by high energetic ball milling method. The saturation magnetization(Ms) and coercivity(Hc) of nitrified powder were increased due to nitride phase.