To reveal the application depth of digital resources in high-quality secondary school geography lessons and its knowledge basis, this study selected 45 junior and senior secondary school geography lesson videos of the 2025 National China Map Press Edition as research samples. Classroom video analysis was adopted, and continuous state units were used to code TPACK knowledge representation, resource types, interaction modes, functional orientations, and application depth. The results show that TPACK and PCK constitute the main forms of teachers’ knowledge representation in the sample lessons. The application of digital resources is characterized by the dominance of one-way presentation, the coexistence of presentation-demonstration and simulation-inquiry functions, and a structure in which shallow application is dominant while deep application also accounts for a relatively high proportion. There is a relatively clear structural correspondence between high-level TPACK integration and deep application, but high integration does not necessarily lead to deep application. The study suggests that the quality evaluation of digital resource application in geography classrooms should further focus on the relationship between resources and learning tasks, as well as the processes of evidence generation and learning output.