This research employed TiN as a model system to study the degradation of ceramic films at high temperature under controlled atmosphere. The TiN films were prepared on Cu substrates by a cathodic are plasma deposition technique. The degradation of TiN films on the Cu substrates at high temperature under controlled atmosphere was investigated using X-ray photoelectron spectroscopy and scanning electron microscopy/energy dispersive spectroscopy. Annealing was performed in the flowing gases including air, nitrogen, argon, and N-2/H-2 = 9 gas mixtures, which possess different nitrogen and oxygen partial pressures. The degradation of the films at high temperature results mainly in color changes associated with the presence of TiO2 and formation of thermally induced fracture of the films. The degradation diagrams at various annealing temperatures and times in the controlled atmosphere were successfully generated. The driving force of the oxidation, i.e. the Gibbs free energy change for TiN and TiO2, was discussed. The thermal stress which induced the fracture of the film was also analyzed.