Improvement of the quality factor has now been an active area of research due to the growing interest of researchers in the field of the photonic crystal-based ring resonator and its applications in photonic devices. The introduction of randomness into the photonic crystal structures has proved to be an effective way to enhance the quality factor. A theoretical model of photonic crystal structure with a size disorder of the rod radius is investigated. The radius of the inner rods of the ring is modulated with the Gaussian random distribution function. The effect of a change in the disorder parameter (standard deviation) on the quality factor of the photonic crystal structure and the effects on the quality factors for variation of the refractive index of the structure and the analyte sample are evaluated.