This paper presents a steady state modeling analysis of thermoplastic phenomena in a Carbon/Carbon brake disk system for an aircraft. A finite element code is developed which allows an effective investigation of thermal-mechanical coupling effects.The finite element analysis results present the pressure distributions and the temperature distributions along the friction surfaces. and heat flux vectors for the present model. The thermoplastic state on any friction surface affects the other friction surfaces each other. Thus, the whole model of brake disks should be analyzed for more advanced results. The use of the orthotropic brake disk is better than the isotropic brake disk as a brake friction material because the contact area of the composite brake disk is larger than that of the isotropic brake disk during the thermoplastic process.