Abstract: The carbon films coated on the inner surface of quartz ampoules in different technological conditions were tested and analyzed by microscope and thrust analytic instrument. The morphology and etching pits of crystals, which growed in these ampoules, were also observed. The effect of the tech- nological parameters on the surface topography of carbon films and the binding force between carbon films and quartz was studied. And optimal technological parameters of carbon coating are obtained, i.e. carbon coating temperature of 950～ 1100℃, the gas-flow rate of 4～ 7ml/h,the carbon coating time of 6h and the cooling time of 12h. Under the condition,the thickness of carbon films is more uniform and its binding with quartz is much stronger. Moreover the as-grown CdZnTe crystal has a smoother surface and lower dislocation density.