In the design of the intelligent 429 bus interface card,a single chip processor and a dual-port RAM are used.The card can deal with the communication data automatically and quickly.Using the dual-port RAM as a single chip and ISA bus data mutual media,the transmission velocity is improved. The address space allocation of dual-port RAM and a share conflict arbitration are discussed.The software of interface card is introduced. Its results show that it has advantage of high velocity and good reliability.