Abstract: In order to study the propagation characteristics of longitudinal guided wave in partly embedded steel pipe, the authors calculate and analyze, on the basis of elastic dynamics theory, the guide waves group velocity, attenuation and dispersion in free pipe and buried pipe. And on the same time, the FEM model is built and the influence of different embedded length is simulated. The results show the velocity of L(0, 2) mode keeps consistent and its attenuations is proportional to embedded length. The experimental result is consistent with theoretical analysis and FEM simulation.