Fe-R-O (R=Hf, Nd and Dy) films were made by reactive sputtering technique and annealed at 400℃. X-ray diffraction and electron diffraction show that nanometer scale Fe grains are embedded in amorphous Roxide matrix. Inplaneferromagnetic resonance was systematically carried out to measure the inplaneresonance absorption spectra and utilized to analyze the relationship between the local magnetization and grain size. The asdeposited samples show obvious uniaxial anisotropy, while annealed samples display weak magnetic crystalline anisotropy at the expense of weakening the uni-axial anisotropy. The local magnetization was calculated based on the formula. (ω/γ)2=(Hres+HK)(Hres+HK+4πMs).It decreases with decreasing grain size, being as only about 30% of the saturation magnetization of bulk Fe. It is also smaller than the bulk magnetization calculated according to the volume ratio of Fe. The linear dependence on the inverse of the grain size indicates a strong surface moment pinning effect.