Abstarct: In this research, a thermoelastic analytical solution and semi-analytical creep solution for the variable wall-thickness conical shell that is subjected to mechanical and thermal loading in the inner and the outer laxyers is presented. By using the first-order temperature theory and the first-order shear deformation theory and the energy method, the Governing equations are derived for different boundary conditions at both ends of the cone. The governing differential equation system is an ordinary differential equation system with variable coefficients, which is solved thermoelastically for a conical shell with two ends and a certain temperature by using the perturbation technique. Then, with the semi-analytical method, the redistribution of displacements and stresses over time due to the phenomenon of creep is determined. The effect of geometry and loading on the thermomechanical behavior and creep behavior of the structure is investigated over time and compared with the results predicted by the finite element method. In fact, the present analysis can be used as an objective function to optimize and estimate the life of the structure and design a structure with optimal behavior.