The magnetic and chemical stability of α-Fe metal magnetic recording particles can be modified by chemical surface coating with silane coupling agents. The results of measurements by TEM, FT-IR, TG-DSC, Mossbauer, EXAFS and VSM etc show that a close, uniform, firm and ultrathin layer, which is benefit for the magnetic and chemical stability, can be formed by the cross-linked chemical bond Si-O-Si. And the organic molecule has chemically bonded to the particle surface oxide layer with Si-O-Fe, which has greatly affected the surface electronic structure and the second shell of Fe atom. However, the organic layer really does not affect the first shell of the matrix Fe atom.