本文简要描述了电动机故障分析中的对称分量法和CAN 总线的结构特点。在分析算法的基础上，结合CAN 总线通信的要求，提出基于CAN 总线的电动机保护的方案，并介绍了设计方案的硬件结构和程序流程图。实验结果以及在工厂生产车间的实际运行情况表明，该设计功能合理、可靠高效，达到了预期的效果。关键字：电动机保护；对称分量法；CAN 总线Abstract: This paper describes the symmetrical components method in motor failure analysisand the structural characteristics of CAN bus briefly. On the basis of analyzing algorithm,satisfying the requirement of CAN bus communication, a solution, including the hardwarestructure and program flowcharts, was worked out to protect the CAN bus. Experimental andpractical results show this method is valid and reliable.Keywords: protect of motor ；the symmetrical components method ；CAN bus