Abstract: The influence of mass matrix on dynamic calculation accuracy of Euler-Bernoulli beam theory and two-node bilinear interpolation beam theory is compared and analyzed by displaying uniform mass matrix and concentrated mass matrix. The superiority of two-node bilinear interpolation beam is revealed by numerical simulation using the finite element program Python. The results of theoretical derivation and numerical analysis show that the grid must be divided before the dynamic calculation of beam element. The increase of mesh density does not improve the dynamic accuracy of Euler-Bernoulli beam using concentrated mass matrix, while the convergence of uniform mass matrix is significantly higher than that of concentrated mass matrix.