A method and apparatus for transmitting data in a coax network, a coax distribution network including an access point and a plurality of coaxial terminals connected to the access point through splitters, a same physical transmission channel is adopted for transmitting uplink data and downlink data between the access point and each coaxial terminal in the coax distribution network, the method including: Step S1: dividing an entire time duration of a physical transmission channel for transmitting information into time slices to constitute an uplink data transmission channel and a downlink data transmission channel; and Step S2: transmitting uplink data and downlink data between the Ethernet access point and each coaxial terminal at different time slices respectively. The present invention is based on a reconstruction of the Ethernet physical layer of the coax distribution network, where the uplink data and the downlink data are transmitted on the same physical transmission channel by adopting a time division multiplexing method, and MPCP protocol is adopted on the uplink for realizing a MAC layer communications between the Ethernet access point and the plurality of coaxial terminals.