A numerical test system named Realistic Failure Process Analysis (RFPA) was introduce into materials mechanics course teaching, and the numerical test results were applied into the classroom teaching to help students’ understanding the elementary knowledge. On this basis, many mechanics phenomena and data information can be obtained through the numerical test, but it can not be obtained by the experiments. Thereby, students can have directviewing and indepth recognization on deformation and failure process of the structure specimen. A case about beam strength is analyzed in the paper. It helps students to integrate theory with practice, stimulate interests of study and research of students, train research quality, therefore to improve the whole teaching effect of materials mechanics.