Abstract: A simple thermodynamic model for fabricating carbon nitride film via magnetron sputtering is suggested. Firstly the most possible surface reactions synthesizing β-C₃N₄, P-C₃N₄ or-(C₂N₂)_n- are selected. Then by solving the thermodynamic model, the partition lines in the growth parameter space are calculated. These lines show the regions where different kinds of films can be deposited. The results are in good agreement with several experimental data.