The amorphous carbon nitride films were prepared by dc magnetron sputtering first　and then were heat－treated at high temperature.DTA　XRD　Auger spectroscopy wer e used to study the difference of composition　structure before and after heat－t reatment.The results showed that crystallization occurred at 1186℃.Heat－treatm ent can induce the crystallization of carbon nitride and the diffraction peaks a ppeared in the XRD pattern.The results of Auger spectroscopy also showed that th ere existed SiCN－riched area and the content of N decreased.