Abstract: Arches supported by other structural members can be considered to be supported elastically at both ends by horizontal springs. An elasto-plastic finite element model is established to study the in-plane ultimate strength and stability of steel circular arches with horizontal spring supports using large deformation theory by ANSYS. Initial geometric crookedness, residual stress and material inelasticity are considered in the investigation. The effects of the stiffness of the horizontal end restraints on the bearing capacity of arches with I-sections subjected to different load cases are studied. Based on the numerical results, formulas for displacement of supports under ultimate strength in terms of the stiffness of ends are proposed. The design equations for pin-ended arches proposed by other researches are used for elastically supported arches, and a simplified design criterion is presented.