Abstract: Base on the stability theory of circular deep arch with large curvature, the formula for calculating the critical load of arch dam is given considering the effect of curvature and shear deformation on the stability of level arch. An iterative solution for transcendental equation is developed for the case that the non-hinged circular arch loses stability. The concept of elastic buckling coefficient is proposed. The results agree well with those of the actual projects by checking the stability of several typical arch dams against elastic buckling. Some conclusions are summarized as follows. The level arch near the top of the dam is prone to lose the integral stability, and the curvature and shear deformation have little effect on the critical load of stability of level arch due to small curvature and thickness. On the other hand, the level arch near the bottom of the dam is not likely to lose the integral stability, and the critical load decreases significantly due to larger curvature and thickness. Shear deformation has larger effect on the critical load of stability of level arch than curvature does. Finally, stronger connection between the dam and dam shoulder leads to higher stability of the dam.