Ontology combined with the development of computer technology in all fields initiated the research of construction and application for so-called "domain ontology". This article starts with the basic concept of computer ontology theory, then gives the oil exploration and development of knowledge management system framework design, and provides a construction method of oil exploration and development domain ontology based on a multi-level business process, and divides the oil exploration and development domain into multistage business activity levels, and takes oil extraction engineering as example and discusses the corresponding knowledge base construction method.