SiCw/Al-18Si composites were prepared by squeeze casting technique. SiCw/Al-18Si composites were remelted before solidification. The effects of volume fraction of SiC whisker on solidification behavior of SiCw/Al-18Si composites were investigated by means of differential scanning calorimetry (DSC) technique and microstructure observation. DSC results indicated that the start solidification temperature and primary silicon peak temperature decreased gradually and the degree of supercooling increased with the increasing of SiC whisker content. SiC whisker and Sr decreased the average size of Si phases and improved the mechanical properties of the composites.