This paper reports the experimental research of monitoring corrosion of rebar in concrete structures using a probe electroplated Fe C alloy film onto the fiber.Its principle is mainly based on light output from the fiber changes with the optical properties of the Fe C alloy cladding,when the fiber probe is exposed to corrosive environment.For monitoring actual corrosion process of rebar in concrete,an embeddable fiber optic corrosion sensor (FOCS) is designed,and embedded in concrete structure along rebar.With accelerated corrosion experiment in an environment test chamber,the result shows that the change of sensors output is coincident with traditional corrosion electrochemical theory in some degree.