A broadband power line network device, comprising: a printed circuit board comprising a primary layout region (162, 450) capable of generating a dangerous voltage and a secondary layout region (164, 455), wherein the primary layout region (162, 450) and the secondary layout region (164, 455) are separated from each other by a first distance and there is no trace pattern between the primary layout region (162, 450) and the secondary layout region (164, 455) to prevent a generation of the dangerous voltage at the secondary layout region (164, 455); a power converter disposed on the primary layout region (162, 450) of the printed circuit board, and comprising a pair of power-receiving terminals (+, -) for receiving an AC voltage, thereby converting the AC voltage into a DC voltage; a network control chip disposed on the primary layout region (162, 450) of the printed circuit board for receiving the DC voltage; a network connector disposed on the secondary layout region (164, 455) of the printed circuit board for transmitting or receiving an external network signal; and an Ethernet signal coupling device (190, 500) arranged between the primary layout region (162, 450) and the secondary layout region (164, 455) of the printed circuit board, wherein if the external network signal from the secondary layout region (164, 455) is received by the Ethernet signal coupling device (190, 500), the Ethernet signal coupling device (190, 500) generates an internal network signal to the primary layout region (162, 450), or if the internal network signal from the primary layout region (162, 450) is received by the Ethernet signal coupling device (190, 500), the Ethernet signal coupling device (190, 500) generates the external network signal to the secondary layout region (164, 455), wherein after the internal network signal is received and modulated by the network control chip, the internal network signal is converted into a modulated network signal and the modulated network signal is output from the broadband power line network device through the power-receiving terminals (+, -), or after the modulated network signal from the power-receiving terminals (+, -) is received by the network control chip, the modulated network signal is converted into the internal network signal and the internal network signal is transmitted to the Ethernet signal coupling device (190, 500). a printed circuit board comprising a primary layout region (162, 450) capable of generating a dangerous voltage and a secondary layout region (164, 455), wherein the primary layout region (162, 450) and the secondary layout region (164, 455) are separated from each other by a first distance and there is no trace pattern between the primary layout region (162, 450) and the secondary layout region (164, 455) to prevent a generation of the dangerous voltage at the secondary layout region (164, 455); a power converter disposed on the primary layout region (162, 450) of the printed circuit board, and comprising a pair of power-receiving terminals (+, -) for receiving an AC voltage, thereby converting the AC voltage into a DC voltage; a network control chip disposed on the primary layout region (162, 450) of the printed circuit board for receiving the DC voltage; a network connector disposed on the secondary layout region (164, 455) of the printed circuit board for transmitting or receiving an external network signal; and an Ethernet signal coupling device (190, 500) arranged between the primary layout region (162, 450) and the secondary layout region (164, 455) of the printed circuit board, wherein if the external network signal from the secondary layout region (164, 455) is received by the Ethernet signal coupling device (190, 500), the Ethernet signal coupling device (190, 500) generates an internal network signal to the primary layout region (162, 450), or if the internal network signal from the primary layout region (162, 450) is received by the Ethernet signal coupling device (190, 500), the Ethernet signal coupling device (190, 500) generates the external network signal to the secondary layout region (164, 455), wherein after the internal network signal is received and modulated by the network control chip, the internal network signal is converted into a modulated network signal and the modulated network signal is output from the broadband power line network device through the power-receiving terminals (+, -), or after the modulated network signal from the power-receiving terminals (+, -) is received by the network control chip, the modulated network signal is converted into the internal network signal and the internal network signal is transmitted to the Ethernet signal coupling device (190, 500).