Abstract: Different SiCp/Al composites were fabricated with molten-stirring method.The influence of cryogenic treatment on thermal expansion properties of different SiCp/Al composites was studied.The results show that SiCp could inhibit the expansion of the material well,and the coefficient of(CTE) thermal expansion beeame lower with the increase of SiCp content.The CTE of the composites increased with the temperature rising.The CTE was related to residual stress.The residual stress and CTE of the composites after cryogenic treatment decreased at room temperature.The more the cryogenic treatment times of the composites,the lower the CTE.