An RJ45 connector device having a switch for changing pin definitions, comprising: a base, having a recess and an accommodation space, wherein a hole is disposed at a position where the recess and the accommodation space are separated from each other; a conversion circuit board, disposed in the accommodation space, wherein a conversion chip is disposed on the conversion circuit board; a set of input pins, disposed within the recesss and electrically connected to the conversion circuit board, the set of input pins corresponding to pins of an RJ45 plug and the definitions of the set of pins corresponding to the definitions of the pins of the RJ45 plug; an information processing circuit board, electrically connected to the conversion circuit board and comprising an information processing chip, and an output circuit board, electrically connected to the information processing circuit board and comprising a set of output pins; characterized in that the RJ45 connector device further comprises a switch circuit board, disposed transverse to the conversion circuit board in the accommodation space, wherein a switch is disposed on the switch circuit board and is located at a position corresponding to the hole, and the switch circuit board is electrically connected to the conversion circuit board;wherein input information (TX+, TX-, RX+, RX-) is processed according to the definitions of the RJ45 plug by the switch circuit board, the information processing circuit board and the output circuit board, and wherein, when the switch is pressed, a conversion signal is triggered, the conversion chip then converts a part of the input information (TX+, TX-, Z+, RX-) input by a designated input pin in the set of input pins into relay information and transfers the relay information, the conversion signal, and the input information (TX+, TX-, RX+, RX-) into the information processing chip; and then the information processing chip converts the input information and the relay information into output information (TD+, TD-, CT, RD+, RD-, CT) through designated processing according to the conversion signal, and transfers the output information (TD+, TD-, CT, RD+, RD-, CT) to the set of output pins for output. a base, having a recess and an accommodation space, wherein a hole is disposed at a position where the recess and the accommodation space are separated from each other; a conversion circuit board, disposed in the accommodation space, wherein a conversion chip is disposed on the conversion circuit board; a set of input pins, disposed within the recesss and electrically connected to the conversion circuit board, the set of input pins corresponding to pins of an RJ45 plug and the definitions of the set of pins corresponding to the definitions of the pins of the RJ45 plug; an information processing circuit board, electrically connected to the conversion circuit board and comprising an information processing chip, and an output circuit board, electrically connected to the information processing circuit board and comprising a set of output pins; characterized in that the RJ45 connector device further comprises a switch circuit board, disposed transverse to the conversion circuit board in the accommodation space, wherein a switch is disposed on the switch circuit board and is located at a position corresponding to the hole, and the switch circuit board is electrically connected to the conversion circuit board;wherein input information (TX+, TX-, RX+, RX-) is processed according to the definitions of the RJ45 plug by the switch circuit board, the information processing circuit board and the output circuit board, and wherein, when the switch is pressed, a conversion signal is triggered, the conversion chip then converts a part of the input information (TX+, TX-, Z+, RX-) input by a designated input pin in the set of input pins into relay information and transfers the relay information, the conversion signal, and the input information (TX+, TX-, RX+, RX-) into the information processing chip; and then the information processing chip converts the input information and the relay information into output information (TD+, TD-, CT, RD+, RD-, CT) through designated processing according to the conversion signal, and transfers the output information (TD+, TD-, CT, RD+, RD-, CT) to the set of output pins for output.