Microstructure and chemical composition changes on the alloyed aluminum surface were investigated using SEM-EDX analysis. A Q-switched Nd:YAg laser was focused to induce breakdown and plasma formation. The high plasma temperature and the shock wave pressure were responsible for speeding up the laser surface alloying process. The rapid heat and cooling process introduced a non-equilibrium condition causing changes in the microstructure as well as the chemical composition of the alloyed aluminum surface. The remelted layer and molten pools were realized after the aluminum received a power density greater than 5 x 10 8 Wcm -2 . The chemical composition change confirms that the convection process had taken place during the alloying process.