The effect of annealing on optical properties of the CN x films prepared by electron cyclotron resonance laser pulse assisted deposition was reported. X ray diffraction (XRD) shows that CN x film samples have basically amorphous structure and very little amount of poly crystalline structures. Raman Scattering spectra demonstrates that the bonds in CN x films prepared at room temperature (RT) are mainly CN bonds, but a few C-C and minim CN bonds. With the annealing temperature increasing,not only appears a new peak corresponding to disordered CN bond near 1357cm -1 in Raman Scattering spectra, but also the comparable accumulations between CN and C-N bonds roughly tend to decrease at first, then increase and then decrease again. It proves that partial hydrogen atoms in the samples are migrated or escaped from the samples. The optical constants of CN x film samples measured by scanning ellipsometry demonstrate that annealing has a pronounced effect on ε 1?ε 2?n?k and spectra shap