The work aims to study the influence of shock angles on the strengthening effect for laser shock peening. TC4 ti-tanium alloy samples were treated by YAG laser system with wavelength of 1064 nm, pulse-energy of 7 J and pulse-width of 12 ns. The surface topography, residual stress and microhardness of the samples shocked in different polarization directions by differ-ent shock angles were obtained. The difference of impact processing effect for different polarized oblique laser was analyzed by the Fresnel‘s law. With the increase of the shock angle, the pit depth of the samples caused by the shock gradually reduced. The depth decrease by the orthogonal polarization laser was more obvious compared with that by the parallel polarization laser, particularly when the angle exceeded 30?. As the shock angle increased, the microhardness of samples gradually decreased. The microhardness decreased slowly for parallel polarized laser. However, the microhardness decreased rapidly for orthogonal polarized laser when the shock angle exceeded 15?. When the shock angle increased, the centeral residual stress increased first and then decreased. The residual stress hole can be solved effectively by choosing the appropriate shock angle in some cases. The conclusions can provide guidance for the laser shock peening trajectory planning of complex structures workpieces.