The performance of optical components for fiber optic gyroscope(FOG) will degrade by ionizing damage effect and displacement damage effect in space radiation environment. Radiation effects on optical fiber, SLD optical source, and PIN-FET detector module were discussed respectively. In order to keep the performance of FOG in space, radiation protection technology was discussed from both radiation shielding and active hardening technology. Given that different optical components have different radiation sensitivity for different radiation damage mechanism, and there has a strict requirement on the weight of spacecraft payload, then the design of shielding was optimized on ionizing damage and displacement damage respectively. The active hardening technologies for every optical component were also discussed based on the analysis of radiation effects on each component.