Abstract: To meet the demanding requirements for data transfer rate and data processing ability in a data acquisition system, the author introduced a symmetric PCI bus interface design in the implementation of a high-speed data acquisition and pre-processing module with two C6202 and one PCI9054 connected symmetrically. The design makes use of the compatibility of C6202's expansion bus and the i960Jx bus standard to connect the DSP chip to the PCI bus, while connecting two DSP chips together through their expansion bus using the programmable logic device. Any one of the three devices in the interface design can then act as the master on the bus to access other devices freely. This scheme greatly enhanced the high-speed data acquisition and pre-processing module's ability of data transfer and data co-processing, making it more practical and universal.