An overhead monitoring method, comprising: receiving a flexible Ethernet, FlexE signal from at least one physical layer PHY interface respectively, wherein the received FlexE signal comprises a FlexE signal with a transmission rate being N times of Y Gbps, N*Y, and a FlexE signal with a transmission rate being a target transmission rate, the FlexE signal with a transmission rate being the target transmission rate comprises at least one of a FlexE signal with a transmission rate of Y 2 Gbps and a FlexE signal with a transmission rate of X Gbps, where Y is a predetermined basic transmission rate and Y at least equals 100, X = Y*C, N is a natural number greater than 1, and C is a fixed coefficient and is a non-integer; de-interleaving the FlexE signal with a transmission rate of N*Y Gbps in the received FlexE signal into N de-interleaved 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 signal and the N de-interleaved PHY signals each having a transmission rate of Y Gbps, wherein M is a natural number greater than or equal to 1; 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 extracted FlexE overheads, and outputting the linear overhead frame for monitoring; wherein, the linear overhead frame comprises each extracted FlexE overhead; the method further comprises performing frame delimitation on each of the M valid data signals comprises: respectively performing following operations on each of the M valid data signals: searching for a FlexE frame header according to a preset frame header pattern; and after the FlexE frame header is found, determining a position of the FlexE overhead to be extracted and a position number i of the FlexE overhead to be extracted in a multiframe, wherein i is an integer ranging from 0 to 31. receiving a flexible Ethernet, FlexE signal from at least one physical layer PHY interface respectively, wherein the received FlexE signal comprises a FlexE signal with a transmission rate being N times of Y Gbps, N*Y, and a FlexE signal with a transmission rate being a target transmission rate, the FlexE signal with a transmission rate being the target transmission rate comprises at least one of a FlexE signal with a transmission rate of Y 2 Gbps and a FlexE signal with a transmission rate of X Gbps, where Y is a predetermined basic transmission rate and Y at least equals 100, X = Y*C, N is a natural number greater than 1, and C is a fixed coefficient and is a non-integer; de-interleaving the FlexE signal with a transmission rate of N*Y Gbps in the received FlexE signal into N de-interleaved 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 signal and the N de-interleaved PHY signals each having a transmission rate of Y Gbps, wherein M is a natural number greater than or equal to 1; 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 extracted FlexE overheads, and outputting the linear overhead frame for monitoring; wherein, the linear overhead frame comprises each extracted FlexE overhead; the method further comprises performing frame delimitation on each of the M valid data signals comprises: respectively performing following operations on each of the M valid data signals: searching for a FlexE frame header according to a preset frame header pattern; and after the FlexE frame header is found, determining a position of the FlexE overhead to be extracted and a position number i of the FlexE overhead to be extracted in a multiframe, wherein i is an integer ranging from 0 to 31. searching for a FlexE frame header according to a preset frame header pattern; and after the FlexE frame header is found, determining a position of the FlexE overhead to be extracted and a position number i of the FlexE overhead to be extracted in a multiframe, wherein i is an integer ranging from 0 to 31.