Laser shock peening (LSP) with different process parameters is applied on TC17 titanium alloy, the distribution of the residual stress of TC17 titanium alloy after LSP is tested, and the microstructure is observed by transmission electron microscopy. The results show that, the surface residual stress of TC17 titanium alloy after LSP increases with the increase of impact number and pulse energy. Severe plastic deformation and high density dislocation are found on TC17 titanium alloy surface after LSP. The density of dislocation increases with the increase of laser impact number and pulse energy.