There exist the generic concepts and semantic relationships in the description of procedural knowledge and strategic knowledge in contract management. In order that contract information could be understood and processed by machine automatically, more semantic descriptions are needed. Ontology has become a promising technology to express semantics. At present, Web ontology languages have been standardized. However, building domain ontology based on OWL (Ontology Web Language) just begins and has a long way to go. In building domain ontology, people should explore the rationality in expressing domain concepts and relations between the concepts, considering the capabilities of OWL (not the capability of natural languages). In this paper, we put forward a framework of contract ontology after considering capabilities to express semantic relations provided by OWL. Then we use Prot?g?-2000 to build OWL representations of the contract ontology and make some analyses. Our exploration might not standardize contract ontology. We explore with the intention to help people better understand the rationality in expressing concepts and relations between the concepts in contract management in order that OWL contract ontology and other domain ontology are improved and standardized as soon as possible.