As an effective application of educational technology, online classrooms became the predominant teaching mode nationwide and globally during the pandemic and even after. In the post-pandemic era and future education landscape, their role is becoming increasingly vital. Both in-person and online classrooms exhibit widespread silence, with online classrooms showing particularly pronounced silence. However, this silence phenomenon in classroom teaching has not received adequate attention. This study employs conversation analysis to conduct case studies on silence phenomena in university English online classrooms, supplemented by empirical research through questionnaire surveys, providing feasible strategies to enhance teaching efficiency in higher education English courses.