Abstract: In situ Al-Cr/Al Composites were fabricated by ultrasound aided technology.Then the reinforced phase were characterized by XRD and EDS,the size,morphology and distribution of the reinforced particle were observed by the use of SEM,and the corrosion resistance of the composite material was studied.The results show that the inter-metallic reinforced particles,polygon shaped and small in size are distributed uniformly in aluminum matrix.Al and Cr will generate inter-metallic compound at a high temperature,which will inter-diffuse,forming an homogeneous mixed reinforce phase.Al-Cr inter-metallic compound has good corrosion resistance,interrupting the continuity of the matrix and inhibiting the deepening and expansion of corrosion.The corrosion resistance of the composite material is related to the content and distribution of the reinforced particles.