Abstract: To optimize the spray forming process and obtain desired Si-Al preform microstructures,it is essential to make a full understanding of the solidification process of the alloys. In this study,a numerical simulation of solidification behavior for spray-deposited Si-30wt%Al preforms has been calculated and discussed. The influence of atomization pressure and axial distance on the Si-30wt%Al droplet temperature and solid fraction was discussed. The calculated results of numerical simulation for the alloy have been verified to be accurate.