Abstract: The knowledge points in the circuit analysis course are more and discrete, and the integration of the course knowledge points is the difficulty of learning. In order to improve the subjective initiative of students’ learning and achieve the opposite effect, the knowledge of geometric duality is introduced into the teaching, and a closed-loop self-certification method of knowledge is formed. This explanation combines the geometric duality construction method and the dual equation conversion method in the dual circuit construction method. Practice shows that after mastering the geometric duality, students can more effectively unify the discrete curriculum knowledge in duality. The use of duality not only saves the teaching workload, but also has important value for cultivating the subjective initiative of students to explore the mystery of knowledge.