Laser shock processing (LSP), also known as laser shot peening, is a novel surface strengthening treatment technology. In this paper, the surface roughness, residual stress and microhardness distribution of Ti834 alloy before and after LSP were analyzed by means of surface roughometer, X-ray diffraction and microhardness tester. And the surface morphology and microstructure of the impact area were characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). The experimental results show that the surface roughness, microhardness and residual compressive stress of Ti834 titanium alloy increase after LSP. Moreover, the depth of the strengthening layer formed after one impact and two impacts was 170 μm and 265 μm, respectively. A large number of dislocation entanglement can be observed in the plastic deformation layer induced by laser shock wave. The increase of dislocation density and the formation of deformation twins are conducive to improvement of mechanical properties of Ti834 alloy subjected to LSP.