Abstract: This paper first analyses all kinds of knowledge description structures and their limitations in the existing Computer Assisted Instruction (CAI) and Intelligent Computer Assisted Instruction (ICAI) systems.Then it makes a new classification of the knowledge components in ICAI systems. The article, on the basis of the above-mentioned,gives a general knowledge description structure model which may cover various types of ICAI systems,support every teaching pettern and include all kinds of knowledge components in ICAI.

Key words: knowledge type, ICAI, knowledge description structure