Flipped classroom (FC) is a popular teaching pattern at the present stage. Based on a review of related literature, this paper rethinks the innovation, effectiveness and perceptions of FC from nine aspects, including the theoretical basis, teaching principles, teaching practice, genesis of effectiveness, effectiveness per se, objectivity and rigorousness of effect evaluation, roles played by technology, influence of different disciplines and cost performance. It is argued that: (1) the innovation of FC needs to be further clarified; (2) the effectiveness of it needs to be further validated; and (3) the perceptions of it remain to be deepened. FC therefore deserves a rational reconsideration. [Spanish translation by Mercè Rius.]