Abstract: Huge change has happened with physical channel of the present Ethernet while compared with that of traditional Ethernet. Carrier Ethernet brings forward higher request to Ethernet physical channel. Under the application environment of carrier Ethernet, it is of necessity to improve the transport performance of the Ethernet physical channel by using a special method. Based on the frame structure defined in IEEE Std 802.3, a kind of frame structure is presented, which comprises FEC(forward error correction) contents and an FEC method is also brought forward. The method includes an error correction function as well as a mechanism of detecting the performance of the physical channel and adaptively adjusting the FEC configuration, so the cost brought by the FEC method can be cut short to the minimum while the error correction performance is guaranteed. An Ethernet interface using the FEC method can communicate with an ordinary non FEC Ethernet interface, so the backward compatibility can be reached. Detailed analysis for the performance of the FEC method is given too, and the analysis result proves that the FEC method is feasible. A kind of network device that carries out the method is designed and a test topology is set up to test and verify the method. The test data show that the method has the expected performance.