Gas turbine disc wheels usually operate at high temperatures. The hot gases contact the turbine rotor rim and blades causing these parts operating under extremely high temperature. Even the different cooling methods were used to lower the disc temperatures, it still remains at the high temperature due to continuous contact between rim and hot gases. Plus, even the cooling methods can reduce the temperature in central rotor area, it in turns increases the temperature gradients which produces the thermal stresses in gas turbine disks. To help understanding the mechanism of centrifugal and thermal stresses generated in gas turbine, a computer-aided modeling and simulation methodology is developed in this research paper to determine the effect of critical turbine functioning parameters and improve the turbine performance. So far, there are few related technical papers published in this research field. This paper introduces the computer-aided modeling and simulation methodology to determine the mechanical and thermal stresses produced in gas turbine. One prototype has been built and tested to validate the results from computational simulation. All gained results can potentially help future gas turbine design.