There are two types of brake system -disc and drum in the commercial vehicle such as trucks or buses. Nowadays the disc brake are used widely because of the thermal efficiency and the safety of drivers. In this paper, modal analysis of the brake disc was performed by using the finite element analysis program, ANSYS. The purpose of this study is to compare the resonance and deformation arising from natural frequency in braking with two types of disc. The results of the FEM analysis show the deformation and natural frequency of the disc brake.