An integrated optical polarization independent reflector on LiNbO 3 using Ti diffusion has been proposed according to the theory of two mode interference in this paper. Its principle has been analyzed. With the beam propagation method (BPM), the reflecting characteristic and adaptability with the wavelength change of the reflector have been accurately calculated. By optimizing its configuration parameters, the reflecting ratio is more than 20 dB (99%). Some actual samples have been fabricated and the measured reflecting ratios of both TE/TM mode have reached more than 18.5 dB in the experiment.