To examine the relationship between early number sense and later symbolic arithmetic competence and how they are connected in young Chinese children. The present study utilized a longitudinal sample of 115 Chinese children aged 3 to 6. Young children completed measures to assess number sense, visual spatial skills (in the fall of their second kindergarten year, K2), arithmetic competence (in the spring of their second kindergarten year, K3), working memory, verbal comprehension, and inhibitory control (in the fall of their first kindergarten year, K1). The results showed that number sense predicted arithmetic competence six months later. Meanwhile, visual spatial skills played a mediating role in this association, but it became non-significant when working memory, verbal comprehension, and inhibitory control were added as covariates. These longitudinal findings confirm the close association between number sense and arithmetic competence in young Chinese children.