ＣＡＮ总线是现场总线的一种．较好的现场总线应该既能传送实时数据也能传送非实时数据．针对实时数据的传送，提出了分布式优先权队列及动态分配晋升机制，并分析了相应的参数．针对非实时数据在ＣＡＮ总线上的传送，提出了入侵型ＣＳＭＡ／ＣＤ协议．解决了两种数据在ＣＡＮ 总线上传输的兼容问题 CAN bus is a kind of field bus. A better fieldbus should be able to send real-time data as well as non-real-time data. For the real-time data transmission, a distributed priority queue and dynamic allocation promotion mechanism are proposed, and the corresponding parameters are analyzed. In order to transmit non-real-time data on the CAN bus, an intrusion-type CSMA / CD protocol is proposed. Solve the two kinds of data in the CAN bus transmission compatibility issues