Sound oral language skills (OLS) are the foundation for academic success, and building language skills through fun learning experiences is essential to children’s language development. This study aimed to investigate the effectiveness of improving the OLS of 5-year-old children in the classroom through drawing activities. Using a case study design under qualitative methods, 4 children were selected as the study participants through purposive sampling for a 3-week drawing activity intervention, specifically from 1 September to 21 September 2023. This study was conducted in a kindergarten affiliated with a university in eastern China, and data were collected through observations, interviews, and teachers’ reflective journals. Observations focused on vocabulary richness and sentence coherence. The results of the study indicated that the drawing activity intervention provided children with rich opportunities to develop their OLS compared to traditional classroom activities. Children’s active participation in classroom interactions through drawing activities enhanced their vocabulary richness and sentence coherence. This study highlights the potential of drawing activities in children’s oral language development and provides valuable insights for educators and policymakers. Thus, it is recommended that educators introduce targeted language development scaffolding strategies in drawing activities, as well as increased collaboration with parents so as to enhance language learning in these activities.