Computational thinking (CT) is an important and essential skill for human beings to master in the 21st century. Although CT has received wide attention since this concept was proposed, the current theoretical models have not well defined the complex relations between CT and other cognitive abilities for young children. To provide insight into this gap, the current study proposed a model in which we hypothesized that CT was significantly related to arithmetic fluency that is viewed as an important domain of mathematics. Additionally, arithmetic fluency was predicted to mediate the relations of CT to other cognitive abilities, including reasoning and creativity. This study tested such direct and indirect relations in children aged 5–6 years. Consistent with previous studies on older age groups, the results showed that CT and arithmetic fluency were significantly related to each other and both were significantly related to reasoning ability and creative thinking as well. Moreover, this study, for the first time, indicated that arithmetic fluency totally mediated the relation between CT and reasoning ability, suggesting that these concepts share conceptual commonalities, such as the cognitive processes related to mathematics or/and abstraction; in contrast, arithmetic fluency did not mediate the relation between CT and creative thinking, suggesting that gaining CT skill may exert direct positive effect on the development of creativity. Therefore, despite the root in computer science, CT is associated with many cognitive and learning abilities in other domains, supporting the importance of including CT into early school education.