Abstract
Ontologies, as a kind of content of semantics resources in the construction of knowledge engineering, have entered into the stage of practical study. The study have discussed the difference between the concept of knowledge in the area of knowledge engineering and the meaning of "being" in Ontology. In this study, how to understand the meaning of knowledge in the area of knowledge engineering was discussed from the restrictions of description of Ontology. The relations between the knowledge, knowledge engineering and ontologies are concerned from the views of understanding the ontologies in the area of computer intelligence. The study suggests that the methods of construction should be different for the three types of knowledge, known, discussing and unknown. And the most important and typical attentions are concluded according to the features of knowledge ontologies of domain, task and application in this paper.