This study concentrated on the role of particle size of silicon carbide (SiC) on dimensional stability of aluminum. Three kinds of Al/SiC composite reinforced with different SiC particle sizes (25 μm, 5 μm, and 70 nm) were produced using a high-energy ball mill. The standard samples were fabricated using powder metallurgy method. The samples were heated from room temperature up to 500• C in a dilatometer at different heating rates, that is, 10, 30, 40, and 60• C/min. The results showed that for all materials, there was an increase in length change as temperature increased and the temperature sensitivity of aluminum decreased in the presence of both micro-and nanosized silicon carbide. At the same condition, dimensional stability of Al/SiC nanocomposite was better than conventional Al/SiC composites.