The high temperature deformation behavior of SiCp/6061Al and 6061Al was investigated by tensile tests of temperature ranged 430-610℃. Billet of 6061Al and 20vol%SiCp/6061Al were fabricated by powder metallurgy process. The billets were hot extruded at 470℃ with a ratio of 85:1. The grain size of 20%SiCp/6061Al composite and 6061Al alloy were measured 2.5㎛ and 3.2㎛, respectively. Tensile test specimens were machined from extruded bar, and followed by solution treatment at 529℃ for 3hr and aging at 177℃ for 8hrs. The stress-strain behaviors of 20%SiCp/6061Al composites and 6061Al were investigated by strain rate change tests at temperature ranged 430-610℃ with strain rate ranged $10^{-4} - 10^{-1} s^{-1}$. The flow stress of SiCp/6061Al composite was higher than that of 6061Al alloy at temperature below 520℃. However, the flow stress of SiCp/6061Al composite became lower than that of 6061Al alloy at temperature above 520℃. The region of temperature and strain rate showing the inversion of flow stress coincides with the region showing the grain boundary sliding. There was no evidence for partial melting at SiC/Al interface based on DSC test conducted at temperature ranged 500-650℃ with heating rates of 10K/min and 3K/min. Elongation-to- failure tests show that the maximum elongations of 20%SiCp/6061Al and 6061Al were obtained 430% and 280% at 863K under strain rate of $10^{-2} s^{-1}$. The fractographies of tensile tested specimens in grain boundary sliding dominant region indicated the intergranular fracture of SiC/Al interfaces and Al/Al grain boundaries. 20%SiCp/6061Al showed a large amount of cavities measured 10.4% after 100% elongation at 570℃. while, 6061Al showed a reduced amount of cavities measured of 2.2% after 100% elongation at 570℃. As a result, SiC/Al interfaces are weaker than Al/Al grain boundary at high temperature. It is considered that the deformation is concentrated on 6061Al matrix and the SiC/Al interfaces are the nucleation sites for the cavities in SiCp/6061Al composites.