Corrosion monitoring system and method

The invention discloses a corrosion monitoring system and a corrosion monitoring method, which adopt alternating current with high and low frequencies for excitation, and can measure internal corrosion and external cracks of a pipeline at the same time. The system comprises a main control module, an excitation module, a pre-amplification module and a signal processing module, the excitation module receives a command sent by the main control module through a serial port and outputs low-frequency sine alternating current or high-frequency sine alternating current; the pre-amplification module receives a differential voltage signal generated between electrode pairs in the pipeline electrode matrix by the output current of the excitation module, and performs two-stage amplification; the band-pass filter receives an output signal of the pre-amplification module and performs filtering according to different low-frequency and high-frequency sine alternating-current frequencies to obtain low-frequency and high-freque