The vibration of beam structures has an important impact on the application of engineering. Taking the bending vibration of the beam element as a case and embarking upon the control differential equations of it, this paper deduced the analysis formulas of the bending vibration of the beam element by boundary element method (BEM), proposed local-interval-step-thinning frequency scanning method, completed the BEM dynamic analysis program of the beam element by Matlab software, and eventually provided the corresponding examples of dynamic analysis of the beam element. The results indicate that BEM is convenient for dynamic analysis of beam structures. Compared with the conventional scanning method, the local-nterval-step-thinning frequency scanning method has higher efficiency and accuracy.  