Entrapment-gas in the carbon fibers reinforced aluminum matrix composites melt could be reduced by vacuum degassing after stirring and mixing to resolve the damage of composites performance due to high gas porosities in prepared composites by stirring method.Relative density of the composites ingot was measured by the Archimedes law to understand effects of temperature of vacuum furnace

degassing time on compactness of the carbon fibers reinforced A356 aluminum matrix composites ingot in condition of vacuum rate of 0.03MPa.The results show that the gas porosities in the prepared composites ingot can be decreased by lower than 2% with degassing for 2 min at 700℃

and interface morphology of the composites was characterized by SEM （scanning electron microscope）

showing ideal interface with gas hole free.