Measurements for photorefractive dynamic properties under polarized light with different luminous intensity and wavelength at $650\mathrm{nm}$ were performed in calcium-doped strontium barium niobate crystals as a function of the time. Experimental results further validated that the different input luminous intensities influence only the saturated time and photorefractive velocity of the photorefractive crystals. Birefringence experiments suggest that an input luminous intensity oscillatory threshold should exist between $64\mathrm{m}\mathrm{W}/{\mathrm{cm}}^2$ and $13\mathrm{m}\mathrm{W}/{\mathrm{cm}}^2$ . The dynamic change of refractive index from self-focusing to asymmetric self-defocusing was also measured and regarded as the mutual results of the nonuniform-intensity incidence and positive thermal lens effect, which was validated by a further experiment based on the Michelson interference. Also, oscillation accompanying change in the dynamic indices was analyzed and attributed to the high dielectric effect as well as asymmetric self-defocusing in this investiga tion.