This study is focused to improve thermo-mechanical characteristics of cross-drilled type of the ventilated brake disc geometry, which has been widely manufactured by automotive and railway industries. Five different linear distance between hole locations, five different distance from the center of the disc and five different angular rotation for hole locations were chosen to obtain variable designs. Numerical experiments were designed according to Taguchi's orthogonal array and grey relation analyses were used to optimize the results. In FEA (Finite Element Analysis), combination of numerical study with Taguchi-Grey techniques not only reduced the number of simulations necessary to optimize the results but also provided an improvement by finding the factors which were not greatly influenced by external or uncontrollable factors. The outcomes of this study will guide manufacturers to produce improved ventilated brake discs by reducing the thermal stresses and thus enhancing the longevity. In this study on the thermal stress of the disc drive of the total surface area and volume/weight and without changing the design variable has been improved from 54% to 13%.