K9 glass film was used as protection coating in order to avoid the surface corrosion of erbium-doped phosphate glass during ion-exchange processing for optical waveguide fabrication. The fluorescent spectrums and fluorescent lifetimes of erbium ions in samples were measured and analyzed. The fluorescent spectrums were not changed after being coated by K9 glass film with different thickness, while the fluorescent lifetimes were reduced by 0.2 ms compared with the raw erbium-doped phosphate glass. The surface morphology was observed by means of microscope and the optical characteristics of planar waveguide were measured with prism-coupling technique. The effect of thickness of K9 glass film on the waveguide fabrication was investigated and the optimal thickness was found to be 60～80 nm. It would provide a good experimental base for further fabrication of active glass optical waveguide devices.