Abstract: Based on homogenization approach, the thermal expansion coefficient and variable stiffness matrices along the longitudes were deduced, and according to pre-buckling membranes theory, the total potential energy for buckling analysis of advanced grid stiffened composite (AGS) conical shells under thermal and mechanical mixed loading was presented. Then, by minimum potential principle, the critical load of AGS conical shells under thermal and pressure loading was predicted. The good agreement between predicted results by provided method and FEA results for a typical example of buckling analysis of AGS conical shells validates the present method. Lastly, by some numerical results, the discussions of the influence of temperature and semi-cone angles on the thermo-mechanical buckling response of AGS trapped conical shells were carried out. It can be seen that the effect of temperature on buckling resistance of the shells increases with increasing the semi-cone angles.