Friction stir powder processing (FSPP) can produce metal matrix composites (MMCs) in the stir zone. Unlike the conventional technologies such as powder metallurgy or molten metal processing, it is still challenging for FSPP to produce high-particle-content MMCs, and the mechanical and functional properties are limited. In this study, a simple repeatable procedure, named accumulative FSPP (AFSPP), is employed to increase the particle content in FSPP composites. The process has successfully accumulated the SiC particles into the pure Al matrix, and the microhardness has constantly increased by the repetition of the AFSPP. The maximum microhardness for the 4-time AFSPP sample has been 133 HV, 5.3 times of the base metal. The volume fraction has achieved 58 % near the maximum hardness point.