The paper describes the ontological approach to the vusual knowledge structuring for the e-learning portal design and development. We will discuss why these topics are increasingly important and describe the experience of ontology developing for Knowledge Engineering courses based on educational course for both undergraduate and aster students of Saint-Petersburg State Polytechnic University and Saint-Petersburg State University. We will also describe"OntolingeWiki" tool for creating ontology-based e-learning portals.