Abstract: When it comes to investigating preschoolers' transitive inference,there seems to be a dilemma.Children should be free from the load of working memory,and they should not compare directly but deduce transitively.In present study,the visual-divided-tasks were created to investigate 3 to 5-year-old preschoolers' length transitive inference.2 (interval length)×2 (layout)×4 (age) mixed design was adopted.240 preschoolers aged 3 to 5 participated in the study sorted in four groups every 6 months.The results indicate the conclusions as following:(1) preschoolers' ability of transitive inference develops quickly during the age of 3 to 4.It's developmental speed peaks after the age of 4 when preschoolers can make transitive inference in different task; (2) transitive inferences of preschoolers are influenced significantly by the kind of tasks; (3) there is a significant correlation between total accuracy and the frequencies of logic transitivity justifications.It was concluded that:(1) children as young as 4-year-old can make transitive inference with educational value to some extent; (2) there are 4 discriminative sequences during the development of transitive cognition,denoted as the embryonic level,transitional level,stable level,and the higher level,which mainly in turn occurred in preschoolers aged 36-42 months,43-48 months,49-54 months and 55-60 months.

Key words: transitive inference, Visual-Divided-Tasks, cognitive process, developmental sequences, preschoolers