Abstract: In order to optimize the carrying capacity of composite stiffened panels, a new design method was proposed using maximum carrying efficiency as an objective. Different compression and bending stiffnessesp matching relationships were discussed for their effects on the critical buckling loads of stiffened panels. The approaching degree of global buckling load, local buckling load and static load was employed as the quantitative standard to scale the structureps carrying efficiency. Under the control of static load, the structural stability was optimized towards the direction of maximum efficiency. An agent model for structure efficiency optimization was built using the panelps macroscopic compression and bending stiffness parameters as variables. This model voids the local optimal point and is more suitable for numerical optimization. The critical buckling load of optimized panel is basically in accordance with the static load applied on it by finite element analysis, which shows a high efficiency and proves the reliability of this method.