Abstract: In order to realize on-line monitoring of metal corrosion based on optical fiber sensors, a distributed Bragg reflection(DBR) fiber laser was used as the corrosion acoustic emission sensor, aiming at on-line monitoring of metal Q235 corrosion acoustic emission. The working mechanism and model of polarized orthogonal DBR fiber laser were studied, and the influence of resonator parameters of polarized orthogonal dual-frequency DBR laser as corrosion acoustic emission sensor on the performance was analyzed. The acoustic emission detection experiment based on polarized orthogonal dual-frequency DBR laser was carried out. The optimum design of polarized orthogonal DBR fiber laser was experimentally studied, and the characteristics of the corrosion stage of Q235 carbon steel were presented. The results show that polarized orthogonal DBR fiber laser can not only detect metal corrosion acoustic signal, but also characterize three major corrosion phases of metal corrosion by the variation of the average beat frequency values with the detection frequency range of 0MHz~1MHz. The research project provides the theoretical and technical basis for the optimization design and fabrication of polarized orthogonal DBR corrosion acoustic emission sensors and networks. It is of great significance on on-line corrosion monitoring of metal corrosion, especially nuclear grade key materials.