Abstract: Intellectual individual difference is an important aspect of individual differences. In recent years, with the relative development of cognitive study, researchers have put forward four approaches about individual differences of intelligence: factor approach, parameter approach, strategies approach and adaptive strategy approach. On the basis of discussing the meaning and the historical context related to the four approaches, current research is reviewed. In general, there are some disagreements about aspects of intellectual individual difference. Future study should improve the theoretical construct; relate the brain- mechanism with the cognitive process; and focus on the non-cognitive factor

Key words: Intelligence, individual difference, factor approach, parameter approach, strategies approach, adaptive strategy approach