Thin films of iron were fabricated on MgO(100) substrates using pulsed laser dep osition technique. The crystalline property and surface roughness of the films w ere investigated by x-ray diffraction and atomic force microscopy, respectively . It is found that the Fe films deposited at 500 and 800℃ are of single phase, and no diffraction from randomly oriented grains or impurity phases can be obser ved. The nonlinear optical properties of continuous 9 nm-thick iron film were d etermined using the z-scan method. The results show that the ultra-thin ir on film exhibits large nonlinear refractive coefficient, n2= 709×1 0-5cm2/kW, and nonlinear absorption coefficient, β=-552×10 -3(cm/W), at the wavelength of 532 nm.