The BH5000C online monitoring and diagnosis system for rotating machinery is a networked information system that integrates monitoring and diagnostic functions, which is developed for large rotating units such as turbine compressor units, turbo-generator units, smoke machine-axial flow fan units.A variety of advanced technologies are adopted to address the different network characteristics of enterprise users. This set of Internet-based equipment real-time online monitoring and diagnosis system has been developed.The system integrates monitoring, diagnosis, alarming, and preventive maintenance. It has a built-in fault diagnosis expert system with human-machine dialogue and automatic diagnosis modes. Large-scale rotating machinery is a key equipment in petrochemical and power generation enterprises, which requires long-term continuous operation. Fault early warning and condition-based maintenance are essential.The BH5000C system can quickly and accurately capture early fault information, realize early warning of faults, and become an essential system to ensure the safe operation of large rotating machinery.