Abstract: Using the OSA-CBM(Open System Architecture for Condition-Based Maintenance) model as the standard structure and adopting the XML/SOAP(Extensible Markup Language/Simple Object Access Protocol) and Web Services technologies as the network conmmunication support,this paper presents a 3-D architecture including function,service and system,which provides a novel mode to the design and development of a network-based monitoring and maintenance system for key equipment.A distributed system for condition-monitoring and fault diagnostics of remote equipment,which is designed and developed based on the 3-D architecture,has been successfully applied to practical engineering projects.