Abstract: The influence of grid's non-uniform distribution on the stability of advanced grid stiffened (AGS) composite conical shells has been studied. The distances between ribs of AGS conical shells vary along the shell longitudes, which ultimately results in the longitude dependence of the stiffness distribution. In this paper, the variable stiffness matrices considering various coupling effects along the longitudes were deduced based on equivalent stiffness model. Making use of Donnell form of relations for shells and the minimum potential principle, the critical load was predicted. The analytical result of AGS conical shells has a good agreement with the experimental data,indicating the validity of the analytical model and method provided. In addition, the non-uniform distribution of grid significantly influences the stability of AGS conical shells. Optimal study and design can be performed using the proposed method.