Abstract: Buckling equation of the spanning pipe partially buried in elastic soil is established. Bending equations of the spanning section and the buried section with axial compression are built with small deflection beam theory. Based on stiffness and deformation characteristics of the buried section, more suitable boundary conditions for the spanning section are obtained. Buckling equation of the spanning section is presented in symmetric buckling mode and anti-symmetric buckling mode, and buckling loads under different soil stiffness coefficients are given by numerical method. Research shows that the buckling load coefficient of the spanning pipe is related to the soil stiffness coefficient only. Simply supported beam model is only suitable for the case of specific soil stiffness, and fixed-fixed supported beam model should be adopted for the case of very large soil stiffness. The buckling analysis of the spanning pipe with buried sections can be performed with the proposed method.