Composite modification layer on γ-TiAl alloy could be available by laser gas nitriding technique which was reinforced by nitrides. The microstructure characteristics of nitriding layer were investigated through SEM, XRD and TEM examination. It is consisted of α, γ, TiN and Ti 2AlN and is inhomogeneous distributed throughout the nitriding zone. The maximum hardness value reaches to 1000 kg/mm 2 and is double that of the matrix one. The effect of nitriding on micro-hardness was also discussed.