Abstract: A Micro-Raman spectrometer was used to study nitrogen doped amorphous hydrogenated carbon a-C:H(N) films, annealed by a focused argon ion laser (514.5 nm) operating at power density of 300, 750 and 1500 W/mm², respectively. During laser annealing, with the increasing of the power density, the peak ratio I_D/I_G of Raman spectra of an a-C:H film without nitrogen increases and the peak of graphite shifts from 1550 to 1598 cm^-1, indicating that the film has graphitized. However, with the increasing nitrogen content in a-C:H(N) films, the graphitization is clearly restrained, indicating that the a-C:H(N) films have higher thermal stability than that of a-C:H films. A laser cold annealing (LCA) mechanism based on the bond excitation energy and thermodynamics is adopted to interpret the results satisfactorily.