Static aeroelastic instability of structures, which is also called divergence, represents an important theoretical and practical problem. Divergence of composite structures has been intensively studied due to increasing utilization of composite materials in the aerospace industry. In this paper, axisymmetric divergence of simply supported, internally ring-reinforced composite shells is considered. The shell is subject to an air flow, directed parallel to the shell axis, and to static axial loading. The analytical conditions of divergence are obtained both for discrete ring stiffeners and based on the smeared stiffeners technique.