Previous cross-cultural comparative studies have claimed the significance of Chinese handwriting experience in interpreting East Asian children’s superiority in spatial and mathematical cognition. However, the potential pathways behind this functioning remain unclear. With 249 fourth grade Chinese primary students as participants, this study explored the association between children’s Chinese handwriting legibility performance with their procedural calculation performance. The results showed that (1) there was a significant direct relationship between Chinese handwriting legibility and procedural calculation; (2) visual-motor integration (VMI) acted as one significant mediator in linking Chinese handwriting legibility to procedural calculation; (3) VMI and then number line knowledge serially mediated the Chinese handwriting legibility-procedural calculation relationship. These findings highlighted one specific linguistic path to mathematical cognition in the Chinese primary school context. Possible explanations for the results, implications, limitations, and future directions are then discussed.