Abstract: This paper presents a buckling analysis of buried spanning submarine pipelines under axial compressive force caused by thermal expansion,in which the seabed stiffness is taken into account.Traditional methods treat each span segment as a simply-supported beam or clamped-clamped beam in practice.A new approach is developed based on Euler-Bernoulli beam theory,taking into account the linear elastic stiffness of seabed and temperature-driving axial force.A fourth order ordinary differential equation governing buried segment in elastic seabed and spanning segment under self-weight and axial compressive force is established and solved.The static deflection and internal force function of both segments are obtained in closed form.Stability criteria of buried segment and spanning segment are established through analyzing the characteristics of static deflection.