To study the effect of laser peening on microstructures and properties of TiAl alloy,TiAl alloy samples were treated by a Nd:YAG laser system with a wavelength of 1 064nm,apulse-width of 20ns,and a pulse-energy of range 0-22J.The surface micro-hardness,roughness,and microstructural characteristics of the samples before and after laser peening were tested with a microhardness tester,a roughness tester and a Scanning Electron Microscope(SEM).The residual stress and pole figures of TiAl alloy were tested with X-ray Diffraction(XRD)and their high-temperature stabilities were analyzed.The experimental results show that the surface micro-hardness increases up to 33.4%,the roughness increases from 0.042μm to 0.285μm,the compress residual stress increases from 20MPa to 297MPa with the pulse energy up to 9J,and the local textures and typical lamellar microstructures are generated.When the samples are heated for 4hat 650℃,the residual stress value and micro hardness values have droped from 297 MPa to 230 MPa,and 377 HV0.2 to 345 HV0.2 respectively,and the(002)poles shift back to the center slightly.It concludes that the laser peening improves microstructures and properties of TiAl alloy significantly.