Abstract: The purpose of this study is to explore the process of children's reasoning based on temporal relations with premises contained "before" and "while" and the factors that affected children's performances. Total 54 pupils aged from 7 to 11 from primary schools participated voluntarily in the experiments. The subjects were divided into three age groups equally. The tests were carried out individually. Four types of problems were constructed in the following way: One-model problem based on four premises with transitive relation; One-model problem based on four premises with irrelevant first premise; One-model problem based on two premises; Multiple-model problem based on four premises. The results showed that: (1) The performances of temporal reasoning on daily events made much progress from the 7 years olds to the 9 years olds; (2) There were no significant differences between one-model problem and multiple-model problem, the number of models seemed not to be a crucial factor affecting children's temporal reasoning; (3) Children made reasoning actively with 5 strategies in which the strategy of transmission with reversal relations was more efficient.

Key words: pupils, temporal reasoning, strategies