The fabricating method and the annealing properties of the ptoton-exchanged LiTaO3 waveguide are reported in this Paper. The refractive index Profiles of the waveguide layer before and atter annealing are given, and the surface refractive index increment and the diffusion coefficients are caculated. It is show that the refractive index increment of the waveguide correlates with the ratio between the annealing time and the exchanging time.