Abstarct: According to widely used in various industries including oil, gas, petrochemical, aerospace, military industry and etc. Analysis of composite truncated conical shells is an important and applied issue and it has been discussed in this study. In the current work, a semi-analytical finite element method for modeling truncated conical shells baxsed on the first order shear deformation theory (FSDT) is used. Geometric stiffness matrix taking into account the effects of temperature change throughout the shell due to thermal load and the effects of mechanical load is calculated. Shell investigated is made of composite material. In addition a variety of boundary conditions is used in static and dynamic analysis. In dynamic analysis, the natural frequency and in static analysis, the thermal, mechanical and thermo-mechanical buckling baxsed on the simplified Sander's theory by taking the different geometric conditions is computed. Some of the most important results of the current study can be noted below, including the desired effect of increasing the thickness on the free vibration and resistance to buckling and on the contrary, the adverse effect of increasing the length and vertex-angle of the cone against buckling.