Monitoring the real-time status of voluntary nodes is a basic task of Quality of Services (QoS) management in grid. The heterogeneity of distributed host resources is an obvious obstacle of grid resources monitoring. An ontology-based approach is presented in this paper to help monitor host resources, focusing on integrating and sharing the status information of grid resources. The ontology designed is originated from Management Information Base (MIB) in network management. The modeling methods are presented in detail, including data type translation rules, class and properties translation rules, and an ontology is proposed in this paper.