Abstract: To resolve students’ cognitive conflicts arising from the intuition that "the whole is greater than any of its parts" when learning about infinite sets, this study systematically constructs a pedagogical framework for comparing cardinalities of infinite sets by integrating the history of mathematics with teaching practice. By creating a "classroom seat model" to intuitively break the cognitive dilemma, five teaching methods are proposed: the benchmark method, the classification method, the density perspective, the logical method, and the constructive method. It is clarified that "one-to-one correspondence" is the core criterion for defining the cardinalities of infinite sets, revealing the logical coexistence of "equipotence" and "proper subset" in the infinite context. The research shows that teaching the essential characteristic of infinite sets-"the whole equals its part"—can effectively facilitate students’ cognitive shift from finite intuition to infinite logic, which holds significant value for cultivating rational spirit and core mathematical competencies.