This paper presents a distributed monitoring approach for detection, visualization, quantification, and warning for pipe corrosion using a single-mode telecommunication-grade fiber optic cable as a distributed sensor. The distributed sensor can be deployed on the surface of a pipe to measure corrosion along the pipe based on optical frequency domain reflectometry. To validate this distributed pipe corrosion monitoring approach, steel pipes were immersed in sodium chloride solution (concentration: 3.5 wt%) for corrosion tests. Strain distributions were measured and used to detect and map corrosion along the pipe. A meso-scale analytical model was developed to link the measured strains to the mass loss of pipe under corrosion. The effects of cable thickness, spatial resolution, and deployment pattern on corrosion assessment were investigated systematically. A threshold-based warning method is proposed based on the unique sensor data.