In order to study and optimize the effect of laser penning on the properties of titanium alloy, a titanium alloy sample is processed using a YAG laser with the wavelength of 1064 nm and pulse energy of 6J, and its micro-hardness and residual stress are examined and analyzed. The experimental results show that the satisfying laser peening appearance can be achieved when the ablative layer thickness is 100 μm, overlapping ratio is 40% and laser peening times is 1 time. So as to, the surface micro-hardness increases from 409.8 HV to 544.6 HV and the compressive residual stress on the surface of laser shocked area reaches up to -320.6 MPa. Laser peening improves hardness and residual stress of titanium alloy significantly. The experimental results show that the effect of laser peening evidently strengthens the titanium alloy by changing the process parameters.