M?ssbauer spectroseopy has been used to study the dispersity of Eu2O3 on the surface of different supports. Changes in M?ssbauer parameters as a function of the europium content reveal the difference of the interaction between Bu2O3 and the support. On the surface of γ-Al2O3, the M?ssbauer isome shift progressively increases toward to that of bulk Eu2O3 with increasing metal loading, suggesting that the crystal phase of Eu2O3 forms gradually. In contrast, on the surfaces of two types of SiO2 the isomer shifts do not change with changing the metal loading in the range of our study. This suggests that Eus03 tends to spread out on the surface as a second layer over monola-yer dispersion. The conclusion obtained by M?ssbauer spectroseopy is in agreement with that obtained by X-ray diffraction