The present invention relates to a method for synchronized communication in access network applied G.hn technology thereto, access network multiplexer (GAM), an access network terminal (GNT), and access network system using the same, which comprises a plurality of domain masters that communicate with the access network terminal; a clock controller controlling at least one of speed or output of the signal that the domain master transmits; and an access network terminal which communicates with the access network multiplexer (GAM) connecting the domain masters and G.hn specification physical layer, and at least one of speed or output of the signal that the access terminal transmits is controlled by the clock control unit. The present invention provides efficient data transmission and high bandwidth to service subscribers with applying G.hn technology to conventional coaxial cable or telephone line, thereby reducing crosstalk occurred in data transmission.