First-principles evolutionary simulations are used to predict the stable compound of Ti 2 CN. Body-centered tetragonal I 4 1 / amd -Ti 2 CN is found to be more energetically favorable than the other Ti 2 CN compounds at 0 K. The phase stability as a function of temperature for all relevant competing Ti 2 CN phases is investigated by means of first-principles calculations and quasi-harmonic approximation. Our calculations predict that I 4 1 / amd -Ti 2 CN undergoes a phase transition to P 4 2 / mmc at 1698 K and then to R 3̄ m at 1872 K. The different effects from the harmonic, electronic and quasi-harmonic contributions to the Gibbs free energy for I 4 1 / amd , P 4 2 / mmc and R 3̄ m phases are compared and analyzed. It is found that both the electronic and quasi-harmonic contributions to the Gibbs free energies significantly affect the phase transition curve of Ti 2 CN. The calculated temperature-dependent lattice parameter is carefully compared with the previous experimental results. We also provide important thermodynamic quantities as the volumetric expansion coefficient and isothermal bulk modulus and discuss their temperature dependence.