Abstract: Based on the first order shear deformation theory, this paper develops a nonlinear finite element analysis method to study thermal buckling behavior of the advanced composite grid stiffened shells with multi-delaminations. In this paper, the temperature-dependent thermal and mechanical properties and the contact effect between sub-laminates of delaminated regions on the buckling behavior were considered, and a constrained model was established to ensure deformation compatibility between the sub-laminates along the front of the delaminated regions. Numerical analysis for some typical circular cylindrical shells (AGS) with multiple delaminations were performed, and the effects of delamination sizes, numbers and areas on buckling behavior of AGS under thermal-mechanical loads were discussed. It can be seen that the advanced grid stiffened shell (AGS) has strong thermal bucking resistance and good damage tolerance. The methods and conclusions drawn in the paper can provide reference for the prediction of anti-thermal-mechanical buckling capacity and damage tolerance design for AGS.