This Paper builds the CAN-bus experimental system based on micro controller STC89C52 and CAN protocol controller SJA1000. First, it shows the structure of experimental system and the network communication mode, and generally elaborates the design principle of software and hardware. And then it gives the design of upper agreement, according to the feature of this experimental system and the characteristics by which CAN bus application layer can be defined flexibly. The authors do Network communication test through testing software which independently designed. The experimental result shows that this CAN bus experimental system is safe, reliable, and has good communication ability.