Grid technology enables to share and use of various heterogeneous resources. However, it is very difficult to satisfy user requirements and benefits of resource providers. This paper proposes an ontology-based resource management model (ORMM). The model builds an ontology of ORMM for computational grid. As using the ontology and the inference based on some rules, we can reflect requirements of resource users, conclude more transactions, and reduce resting resources. To evaluate performances, the number of transactions, transaction period, and cumulative profits are measured. In experiments, ORMM increases about 32% of greater transactions, reduces about 40% of transaction period. Experimental results demonstrate that the proposed model can improve the efficiency of resource management in the computational grid environment.