Digital fiber-optic gyroscope with linear scale factor, phase high accuracy, dynamic range, etc. This article proposed one kind of closed-loop digital fiber optic gyroscope system based on DSP, and designs the closed-loop fiber-optic gyro for signal detection and processing circuit, and the whole digital closed loop of fiber optic gyroscope light path part and circuit of the concrete analysis. With DSP as logic circuit, make the gyro operation speed and reliability have improved greatly.