Abstract: For large curvature arch, the neutral axis does not pass through the centroidal line of the cross-section, so the moment of inertia is not consistent with the second moment of area. When the dimensions of cross section are relatively large for the arc length, shear deformation must be considered. From the views of these aspects, an analytical model for deep arch is presented, which can consider the influences of large curvature and shear deformation. Under the uniformly distributing radial load around the arch axis, the in-plane stability of circular arch is investigated using analytical method. The results of different theories are compared. The critical parameters of buckling load parameter and subtended angle are discussed for elastic stability and plastic stability.