The hatstringer has large cross section and the cross section is closed by flanges and skin ,which leads to high stability when it compressed. For this reason the hatstringer is widely used in composite panel. This paper optimizes the hatstringer section in the condition of localbuckling and crippling by MATLAB, and obtaines the buckling strength as function of hatstringer width and the angle between hatstringer width and the waist, and the crippling strength as function of hatstringer width and the angle between hatstringer width and the waist. These functions can provide references to designers in the preliminary design.