：Counterfactual thinking could be divided into additive, subtractive and substitutional counterfactuals according to the characters of antecedent. It also could be divided into upwards and downwards counterfactuals according to the characters of consequent. At present there was no coincident conclusion about at what point the children began to create counterfactual thinking. Harris et al and Gergely et al found children could conduct counterfactual reasoning at 2-3. However, Riggs indicated that children couldn’t conduct the counterfactual thinking at 3, and it also had difficulty at 4 years-old and 5 years-old. Zhang Kun discovered children of 3-year-old made mistake easily, and children of 4-year-old almost could accomplish the counterfactual reasoning. Chen Y.H. et al found all the children could conduct counterfactual reasoning from 3-5. Counterfactual thinking included comprehensibility and production, the two abilities produce at different stages. Comprehensibility was the antecedent of production. Children could understand didn’t mean they could cerate spontaneously. The general discussion about “When children could possess the ability of counterfactual reasoning” could create different perspectives. Therefore, this study investigated the development of 2- to 4- year-old children’s comprehensibility of counterfactual thinking under three kinds of motivational conflict which adopted storytelling method. The motivational conflict included double-approach conflict, double-avoidance conflict and approach-avoidance conflict. 76 2-to-4 year-old children were selected as participants. This study included three experiments and it adopted self-made stories which were familiar with children. After children listened to the stories, they answered the questions “yes” or “no” to indicated whether the questions were true or false. The first experiment examined the comprehensibility of antecedent counterfactuals, while the second one looks at their ability to comprehend different directions’ consequent counterfactuals. The result indicated: (1)The scores of 2-year-old children’s additive and subtractive counterfactuals were significantly higher than that of substitutional counterfactuals.(2)There was significant difference among three age groups in subtractive counterfactuals tasks.(3)Under approach-avoidance conflict condition, additive and subtractive counterfactuals were significantly higher than that of substitutional counterfactuals. (4)There was significant age difference in young children’s consequent counterfactual comprehension tasks.