Disclosed are an overhead monitoring method and apparatus, and a non-transitory computer-readable storage medium. The method may include: receiving a flexible Ethernet (FlexE) signals from one or more PHY interfaces respectively; de-interleaving each FlexE signal with the transmission rate of N*Y Gbps in the received FlexE signals respectively into N PHY signals each having a transmission rate of Y Gbps; selecting M valid data signals from the FlexE signal with the transmission rate being the target transmission rate in the received FlexE signals and the de-interleaved PHY signals with the transmission rate of Y Gbps; removing each pad from each of the M valid data signals, performing frame delimitation on each of the M valid data signals, and extracting each FlexE overhead from each of the M valid data signals; and generating a linear overhead frame based on the extracted FlexE overheads, and outputting the linear overhead frame.