Powder metallurgy (PM), as an important method of fabricating SiC particle reinforced aluminum matrix (SiC_p/Al) composites, has advantages in obtaining good interfacial bonding and enhancing tensile strength over casting or infiltrating method. The primary process of the PM method involves mixing, compaction and subsequent secondary plastic deformation. Especially, secondary plastic deformation is an important process to destroy the oxidation film on the Al particle surfaces and enhance Al-SiC bonding. However, the incorporation of the SiC particles restricts plastic flow ability of the composite and makes it difficult to be subjected to heavy single-step plastic deformation, such as single hot extrusion, hot rolling or hot forging. Instead, multi-step deformation is a critical processing approach for the SiC_p/Al composites with low deformability. However, the previous attentions were mostly focused on single-step processing, multi--step plastic deformation of the SiC_p/Al composites was seldom discussed. In this paper, 20%SiC_p/2009Al (volume fraction) composite was fabricated using a common PM method and the effects of double extrusion on the microstructure and tensile property of the composite were investigated. It is indicated that the double extrusion could refine the SiC_p size, align the SiC_p and increase the aspect ratio of the SiC_p, but did not exert critical effects of the grain size and <111> texture of the matrix. However, the average distance between the SiC_p along the extrusion direction increased after the double extrusion, more easily inducing a SiC_p-poor band which aligned approximately perpendicularly to the extrusion direction. This resulted in a decrease in the strength and an increase in the elongation along the extrusion direction.