Ontologies are one of the most popular and widespread means of knowledge representation and reuse. A few research groups have proposed a series of methodologies for developing their own standard ontologies. However, because this ontological construction concerns special fields, there is no standard method to build domain ontology. In this paper, based on discussing and analyzing representative ontology building methodologies, the authors propose a knowledge engineering approach to build domain ontology by combining software development life cycle standard IEEE 1074-2006 with design ontology criteria proposed by T. R. Gruber. The authors use the ontology editor Hozo to develop a marine biology ontology for an e-learning course. They verify the validity and rationality of marine biology ontology by applying it to a practical system called OASIS. The authors then demonstrate the applicability of their proposed knowledge engineering approach. (Contains 1 table and 7 figures.)