Abstract: For meeting the semantic demand of the spatial information grid and expanding the data types of computer grid, the ontology and LDAP (light weight directory access protocol) are combined to make a resource management system of spatial information grid. It can filtrate the nature of the local ontology systems to construct a virtual organization which can provides a global directory service. In conclusion, the semantic grid of spatial information system, which combines ontology and LDAP, can improve the ability of the integration and interoperability of spatial information grid