Three compositions Mg-Al laser cladding alloys have bean obtained on pure Mg substrate, preliminary p hase constitutions were identified, the effect of laser processing parameters upon the microstructure was investigated. The results indicates that the nonequilibrium Mg alloys are different from the corresponding equilibrium alloys to a great extent in respacL of phase constitutions, fractions of phases and solid solubility due to the quick cooling associated with laser cladding. The constitutions and solid solubility due to the quick cooling associated with laser cladding. The constitutions and solid solubility can be controlled by changing the laser processing parameters in order to yield the nonequilibrium alloys with desired microstructure and properties.