The present study was conducted to analyze which the geometry of vents in motorcycle disk brakes affects the surface of the disk. In order to analyze the thermal characteristics of disk brakes, thermal deformation analysis and thermal stress analysis due to heat transfer was carried out through the finite element analysis for ventilated disk and solid disk. By comparing the maximum temperature in the braking process, the ventilated disk showed a lower temperature than the solid disk and effect of temperature increase and decrease, depending on the vent area generated in the flange part of the disk. The thermal deformation in ventilated disk type occurs in all directions by 0.1162 mm, thermal distribution in the circumferential direction showed large deviation, about 0.017 mm due to the vents.