Under the background of national "golden course" construction, research-oriented teaching not only emphasizes the unity of "teaching" and "learning", but also attaches importance to the integration of "teaching" and "research", which has become the focus of teaching reform in higher education at present. Incorporating research-oriented teaching into mechanics courses can better stimulate students' learning enthusiasm and innovative spirit, deepen their understanding and mastery of knowledge, and pay more attention to the engineering application of mechanics knowledge. Elasticity is one of the most difficult courses for engineering undergraduates. Its essence is to solve the boundary value problem of partial differential equations under given boundary conditions. However, the difficulty of solving elastic mechanics is that it is greatly difficult to satisfy the boundary conditions. Therefore, in the teaching practice of elastic mechanics, taking Saint Venant's principle and its application as an example, the design and practice of research-oriented teaching case are implemented. Through the in-depth elaboration and extension of the basic concepts, basic problems and basic methods in the basic teaching contents, combined with typical engineering examples, how to effectively understand and flexibly apply Saint Venant's principle in different local boundaries is discussed in this study. The effect of teaching practice shows that carrying out research-oriented teaching in mechanics courses can enable students to more deeply understand the essence of mechanics and the flexibility of its application, and then feel the beauty of mechanics.