Objectives Mastering Chinese handwriting is a fundamental skill, yet it poses a challenging task for children with intellectual disability (ID). Socioeconomic status (SES) and home literacy environment (HLE) are two important family factors known to influence children’s academic achievement. This study aimed to explore the HLE’s role in SES’ influence on Chinese handwriting skill of children with ID. Methods Chinese handwriting skill was tested directly on 192 children with ID (7-12 years old), while SES and HLE questionnaires were completed by their parents. Data entry, analysis and structural equation modeling were performed using the Statistical Package for Social Sciences software. Results SES was shown not directly correlated with any of the three handwriting skills (β = 0.02, p > 0.05). Instead, the former influenced the latter indirectly via HLE; informal HLE played a complete intermediary role in this relationship (SES-informal HLE: β = 0.42, p < 0.001; informal HLE-handwriting skill: β = 0.41, p < 0.001), while formal HLE had no effect (SES-formal HLE: β = 0.34, p < 0.001; formal HLE-handwriting skill: β=-0.10, p > 0.05). Conclusions SES influences Chinese handwriting of children with ID via mediation by informal HLE. These findings emphasize the importance of maintaining high SES and creating rich HLE in the development of Chinese handwriting skill of children with ID.