Piston is considered to be heart of the engine. It is one of the most stressed parts, operating at very high combustion pressures and temperatures. Despite the technological advancements in design and material selections, there are significant cases of piston damage. This has been the motivation for us to perform a dynamic stress analysis on the piston. In this work basic dimensions of various parts of the piston is calculated based the thermal and structural loads. The model is crated using the creo software according to the dimensions. Then the model is imported on the ansys software and applying the boundary condition. In this thermo mechanical analysis is done by using the ansys workbench. The stress values are compared from the theoretical and FEA model results. Finally found that the design is safe for that maximum loading of the vehicle.