A system and a method for automatically generating new concepts based on existing ontologies are provided. The system creates new concepts in existing ontologies based on new concept descriptions expressed in a natural language format, and comprises: a normalizer for receiving and parsing the new concept descriptions so as to transform them into normalized one and output them, wherein said normalized concept description includes one or more description part(s) having kernel concepts, said description parts can only contain the terms which can be identified in said existing ontologies, and each of said kernel concept contains a headword and zero or more property(s); and a new concept factory for, based on the normalized description of the new concept, identifying the kernel concepts in each normalized concept description part, and extracting the identified kernel concepts, related properties, and the relations among the kernel concepts for a user to create new concepts according to existing ontologies. Therefore, ontologies will be easier to be managed, reused and expanded, while keeping smaller size and less complexity of the ontologies.