A data interfacing apparatus and method of a print head chip are provided. The data interfacing apparatus includes a drive module to output a low-speed signal with a slow transmission speed and a high-speed signal requiring a fast transmission speed, a connection cable transmitting the low-speed signal and the high-speed signal, and a print head chip to operate in response to the low-speed signal and the high-speed signal transmitted through the connection cable, wherein the drive module includes multiplexers to perform a switching operation so that the connection cable is earthed to a ground in response to the high-speed signal, and wherein the print head chip includes de-multiplexers to perform a switching operation in response to the operation of the multiplexers.