Abstract: The shear buckling of webs is apt to occur when the thin plate aluminum girders are loaded under shear forces. But the post-buckling strength of the web plates is considerable since the frame composed of flanges and stiffeners can restrict the deformation of webs. Several theoretical design methods for the shear carrying capacity of aluminum girders are introduced, and the veracities of different methods are appraised by a comparison with foreign experimental data. The stress-field rotation method is found to be more exact, and some questions about its theory and application are discussed. Some modifications are performed for the stress-field rotation method. Constraints that flange and stiffened rib impose on web plate and contributions of flange to shear strength are both considered based on the existing method. Therefore the more accurate prediction of the shear carrying capacity of aluminum girders can be gained.