Resource management system is the core component of a Grid system. It has two important functions: resource publication and discovery. This paper presents an ontology-based model for Grid Resource Publication and Discovery (GRPD). We adopt multiple domainspeci fic registries to manage corresponding resources of a Virtual Organization (VO) in order to obtain high GRPD efficiency. Resource descriptions and resource requests are all based on domain-specific ontology. The ontology-based matchmaker of the domain-specific registry plays the important role in resources selection. The "Index" node of a VO hosts the general registry. Other domain-specific registries are distributed in the VO. This is a two-level registry mechanism. A large-scale Grid system may contain many VOs. "Index" nodes from various VOs connect to each other in the peer-to-peer mode instead of the hierarchical mode.