<p>Picture book reading is a well-recognized method for enhancing language skills in children. While it benefits children universally, its impact can be particularly significant for those facing socio-economic disadvantages, helping to bridge early language development gaps. However, the effectiveness of conventional picture book reading largely depends on sustained high-quality adult–child interactions, posing significant implementation challenges in rural mountainous areas with limited educational resources and a shortage of trained educators. To address these barriers, this study developed a cost-effective, easily implemented intervention that integrates scientific inquiry (a series of processes that children use to explore the surrounding world and construct scientific knowledge) within picture book reading activities to support language development in 4–5-year-old children with migrant worker parents in these remote areas. The intervention lasted for an entire academic year, with two post-tests conducted at the end of the first semester and the end of the academic year. The results showed that 4-year-old participants exhibited significant vocabulary breadth growth during the mid-test, though these gains were not sustained in the post-test. Conversely, 5-year-olds did not show significant improvements in vocabulary breadth but did demonstrate notable enhancements in vocabulary depth and oral expression during the post-test. These results suggest that integrating scientific inquiry with picture book reading can substantially enhance language skills among children with migrant worker parents in rural settings. The study also highlights the necessity for tailored intervention strategies that consider the developmental stages and educational contexts of different age groups. Given its low cost and practicality, the intervention could serve as an effective and adaptable educational tool to foster language development in economically disadvantaged areas.</p>