In order to satisfy the need that Imbedded industrail computers through PC/104 bus control programmed amplifiers with SPI interface, the paper researches the communication protocols of PC/104 bus and SPI bus, proposes the interface design scheme of the SPI bus converted from PC/104 bus on the basis of the nonvolatile flash framework of the FPGA chip and design ideas of the SPI control state machine, verifies the validity and feasibility of the design scheme through simulation and experiment.