KTP planar waveguide is formed by combining ion implantation with ion exchange.The influence of ion implantation on the ion exchange waveguide are studied.The characterization of the waveguide is studied by the prism-coupling method,and the results indicate that positive change in refractive index occurs in the waveguide region.The irradiation damage and the Rb distribution are analyzed by means of the Rutherford backscattering spectrometry technique,and the results show that the lattice damages formed by ion implantation act as a diffusion barrier at about 2.8 μm under the surface,which stop the Rb ion and K ion exchange in the deeper depth.