A carbon film was deposited on the inner wall of a quartz crucible by vacuum evaporation. The effects of gas pressure in the crucible on the carbon film surface morphology and the binding force between the carbon film and the inner wall of the quartz crucible were studied. When the gas pressure was increased from 4 Pa to 12 Pa, the surface roughness of the carbon film increased and large particles appeared on the surface, whereas the binding force between the carbon film and the inner wall of the crucible weakened. When the gas pressure was 12 Pa, the carbon film peeled off. GaSb crystal ingots were prepared by the vertical Bridgman method, and the effects of the carbon film on the ingots' microstructure and properties were studied. When there was no carbon film on the inner wall of the crucible, the dislocation density of the crystals was the highest, their hardness and resistivity values were the largest, and their carrier mobility was the lowest. When the gas pressure was 4 Pa, the crystal surface was flat and the dislocation density of the crystals significantly decreased. The hardness and resistivity values also decreased and the carrier mobility significantly increased. When the gas pressure was 12 Pa, the hardness and resistivity values of the crystals gradually increased, whereas the carrier mobility gradually decreased.