A bus data interface, structure and method for transmitting the data of a PCI bus is disclosed. The bus data interface comprises a high-bit transmitting buffer, a low-bit transmitting buffer, a multiplexer, a strobe generator, and a data distributor. The strobe generator utilizes the bus request signal and bus grant signal to transmit a data strobe signal in response to the PCI clock. According to the rising edge and falling edge of the data strobe signal, the data distributor retrieves data according to the data strobe signal. Further, the invention is compatible with the original PCI bus and allows the PCI bus to transmit data with a dual speed.