The optical characteristics and waveguide index profiles of Z-cut LiNbO3 optical waveguides which fabricated by using a new proton source formed by a mixture of adipic and benzoic acids with different values of the adipic-benzoic acid concentration ratio were studied.The experimental results show that the optical waveguides present β4-phase when high concentration ratio, while present β3-phase when relative low concentration ratio under the exchange temperature of 230℃ exchange time of 6 h. The higher the concentration ratio, the greater the surface refractive index change and waveguide depth of the optical waveguides in β4-phase, and the difference of optical properties in β3-phase is not significantly. The optical waveguides fabricated by using single benzoic acid and 60% ratio dilution were analyzed by double crystal X-ray diffraction. The results give useful information in making optical waveguides and to understand the physical mechanism of refractive index change in the LiNbO3 optical waveguides.