As smart classrooms are gradually introduced into college teaching, multimodal instruction has become a key approach to improving the quality of college English Teaching. Through the integration of diverse digital resources, such as text, audio, video, and interactive platforms, multimodal teaching offers college students an engaging and varied learning experience. In this study, a dual-coding analysis system is constructed for smart classroom environments, incorporating interactive teaching and learning of college English. Additionally, Kendall’s coefficients are utilized to verify its effectiveness. The research explores strategies for efficiently integrating digital resources to optimize college English teaching outcomes. Based on multimodal teaching theory, the study examines integration strategies for various digital resources and evaluates their impact on students’ language proficiency, engagement, and autonomy in learning. The strategic use of digital resources enriches classroom content, enhances students’ comprehensive language skills and cross-cultural awareness, and supports the innovative development of English teaching at the college level.