Objective To transform the equipment with traditional RS232 interface into that with CAN connection interface.Methods On the CAN main line,node is the station for information receiving and transmission in the network.The intelligent node can establish the work way ID,the address and the baud rate through the programming.It is mainly composed by the singlechip and the programmable CAN correspondence controller.Results The hardware and software were designed.SJA1000 initialization,transmission and receiving subroutines are including in the software design.Conclusion CAN is a kind of excellent field bus with high reliability,low cost and has been applied in many fields.It has already formed the international standard and been viewed as one of the most widely used field buses in future.Lots of traditional equipment with RS232 interface are facing the problem of CAN interface transformation.