Abstract: The normal stresses of pure bending of a single rectangular cross-section beam, laminated beam and composite beam have been theoretically analyzed and calculated and experimentally tested by electrical measurement method in this paper. Through the analysis of the measured data, the correctness of theoretical calculations and experimental methods are verified, and the normal stress distribution laws of the three beams are revealed. The data shows that the normal stress of pure bending of the laminated beam is the largest, followed by that of the composite beam, and that of the single rectangular cross-section beam is the smallest. In addition, the reasons for the large errors of some experimental data are analyzed and discussed. By increasing the content and difficulty of the experiment, it is conducive to promote students to master more knowledge of material mechanics and exercise their practical skills. The result can provide a reference for the experimental teaching of material mechanics in other colleges and universities.