Abstract: Based on previous studies，the vertical channel stiffeners with torsional rigidity are first installed，then one transverse strip stiffener with no torsional rigidity is installed，numerous SPSWs with cross double-sided stiffeners are analyzed with finite element elastic buckling analysis method，formulas are presented to calculate SPSWsshear buckling critical stress and stiffenersthreshold rigidity． The results of calculations show that，the accuracy of the formulas is good and they are reasonably conservative; key factors affecting stiffenersthreshold rigidity are aspect ratio of panel ， the number of vertical stiffener and thickness ratio of vertical and transverse stiffeners．