Nowadays, the use of polymer-based composites has been growing. Composites due to mechanical, chemical and physical properties are widely used, but the inherent combustion of these materials and the lack of strength at high temperatures, especially when exposed to the fire is one of the challenges of using composites in industries. When composites are exposed to fire, matrix of composite decomposed with heat release, smoke, soot and toxic fumes. Due to the influence of fire on the composite structure, several thermal processes occur such as thermal conductivity in the structure, production and escape of the gases from the composite and resin decomposition. The aim of this study is the investigation of the effects of fire on the composite structures. Analysis of composite resistance to fire, determine the amount and duration of the fire-resistant composite as well as the effects of thermal stress in composite structure requires thermo-mechanical analysis of the composite. ABAQUS software is used for solving the problem in this study. Appropriate model for analyzing the thermal and mechanical parts of the problem according to the governing equations is developed and imported to the Abaqus software through Abaqus subroutines. Thermo-mechanical model validated with the results of valid studies. Finally, this model is used for thermo-mechanical analysis of a composite cylindrical structure exposed to the fire. The results showed that by estimating the failure time of the composite, it is possible to determine the amount of load that can be applied to the structure under different conditions of fire.