Abstract: In order to reduce the influence of backscattering on the ring laser gyro, backscattering properties in the passive ring cavity was investigated. First, stable solutions of forward and backscattering light intensity and their temporal evolutions for quick turn-on and turn-off of incident light were obtained. Second, full width at half maximum of forward and backscattering light in the ring cavity as a function of incident laser frequency was derived. In the end, variation of forward and backscattering light as a function of incident laser frequency with different frequency scanning speed was discussed. It is found that the whole backscattering intensity is much larger than the single round backscattering intensity and full width at half maximum of backscattering light intensity is 0.64 times of forward light intensity. These findings are of some help to the measurement of backscattering as well as measurement of cavity loss using laser frequency scanning.