In recent years, the performance of an interferometric fiber optic gyroscope (IFOG) has been increased a lot and widely used for dynamic angle measurement. In this paper, we present an investigation on measurement uncertainty of the IFOG and propose a comparison angular vibration calibration approach based on an IFOG. The operation principle of the closed-loop IFOG is introduced, and its error model in angle measurement is derived. Furthermore, the measurement uncertainty components in angular vibration calibration are analyzed by comparing with primary angular vibration calibration. By using a standard angular vibration system in the Nanjing Institute of Measurement and Testing Technology, China, the angular vibration calibration capability of the IFOG is evaluated within frequency range of 1–200 Hz. In addition, the traceability of this proposed calibration approach is also discussed.