In this paper, a novel fiber-optic heterodyne detection technique of rotation rate is described. Using electro-optic frequency shifter and highly birefringent single-mode fiber, the heterodyne fiber-optic gyroscope system no more needs the use of acousto-optic devices and is free from the direct-current drift in the electronics. In addition, the reciprocity of the optical path in the system is improved. Preliminary experiments have shown a good linearity of the scale factor.