The surface layer of the samples of Al4.5%Cu1.0% Si alloy was developed by CO2 laser using TiC and WC particles. Because the oxide film on the surface it was impossible to introduce the TiC particles into the melt, as the WC particles could broken the oxide film and could penetrate to the melt. The microstructure of resolidified layers were cellular or dendritic with cast texture. The bands were overlaped and so the resolidified structure was partly heat treated. The carbide particles reacted with the melt.