Abstract: The preparation of metal sensitive film is the focus of research in optical fiber sensor with metal sensitive film.In this paper,the principal of this kind of sensors was introduced and the Fe-C sensitive film was prepared by the method of electroplating on optical fiber with Cr film as middle conductive layer made by magnetron sputtering.The structure of Fe-C sensitive film was analyzed by means of SEM and XRD.Corrosion behavior of Fe-C sensitive film in 1% HCl solution shows that output power was increased sharply in corrosion process and the signal response time of Fe-C sensitive film in different thickness was different.Microscopic observation in corrosion process found that the sensitive film would be peeled piece by piece when it was corroded to some extent.