The present invention is directed to an Ethernet communication method and system which are based on the MMC/SD interface. In the invention, the communication system includes at least one master device and at least one slave device, the at least one master device and the at least one slave device are connected via MMC/SD interface and communicate with each other on the Ethernet. The Ethernet communication method and system disclosed herein enables the device with the MMC/SD interface to act as a node in the network, and thus greatly expanding the application domain of such devices.