Abstract： The high temperature behaviours of evaporated thin films of copper alloys (Cu-Ti, Cu-Sn-Ti, Cu-Si) on carbon substrate have been studied in heating stage of TEM and HVEM and recorded by a video tape recorder. The diffraction contrast of the grains in Cu, Cu-Ti and Cu-Sn-Ti films begins to vary rapidly at about 640, 700 and 750℃ respectively. The vacant areas in these films expand rapidly above about 660, 750 and 800℃. Finally the isolated islands are formed. The balling of these films on graphite and diamond substrate has been observed by SEM after heating to 750-850℃. The different morphology of the balling on the surfaces of diamond (100) and (111) is due to the different wetting abilities. The expansion rates of the vacant areas in these films have been calculated by using the model of surface diffusion under different curvatures. The calculated values agree with experimental results in the order of magnitude.