In this paper the sensitivity of strain rate and size effect with different particle volume fraction in SiCp/Al Composite were studied through the experiment. Specimens with 40% and 30% SiC particle volume fraction were made. There are three types of particle sizes in each volume fraction. The sensitivity of strain rate and the effect of particle size in Al matrix composites reinforced with the different volume fraction were investigated, using the split Hopkinson pressure bar and Instron5882 universal material testing machine. The surface microstructure of the specimens in each composite was examined using optical microscopy and SEM. Through the strain-stress curves, the sensitivity of strain rate can be obtained. The experimental results show that the sensitivity of strain rate increases with the increasing of particle volume fraction. At the same volume fraction, the size effect were observed obviously and higher flow stresses were obtained in the composites reinforced with small particles than that in the composite with large particles.