Abstract: Classical strength theories are the key and difficult points of the course of mechanics of materials. During classroom teaching, teachers often focus on the elaboration of basic contents of strength theory, and ignore its historical sources and logical thinking, resulting in unsatisfactory teaching effects. Combining with engineering cases, the historical evolution process of the classical strength theories are traced in this paper, and the scientific research methods behind theories are explored. Furthermore, the core teaching ideas of the classical strength theories are summarized, which can help students to sort out the logical relationships in the establishment of the knowledge system. Practices show that the above teaching methods are beneficial to stimulating students' interest in learning and cultivating their innovative thinking abilities.