This study is aimed at investigating the features of expertise and their influences on intuitive thinking or intuition. For this purpose, current research trends on the expertise were reviewed. Since the pioneering work on chess expertise by de Groot(1946) and Chase and Simon(1973) had been initiated, most studies of expertise have been focused on exploring specific performance differences between experts and novices. The studies of expertise have usually been attempted based on two distinctive generations so far. The conclusions obtained from the attempts of these two generations were that the nature of expertise had been focused on the features of knowledge base, of problem representations and higher order problem solving strategies, and of pattern recognition. In terms of performing of these features, experts had been said to be extremely outstanding in comparison with novices. Thus, experts are seemed as very efficient cognitive processors. The most important result obtained through these studies is that expertise is the strong factor to trigger the intuition or insight. This is proved by the fact that experts has powerful elaborated and organized knowledge structures leading to their efficient cognitive activities. This fact have been discussed from the views of information processing models and connectionist or PDP models. Finally, the directions of the future research on expertise and intuition, and their educational implications were also tried to be discussed.