Abstract: A Fiber Optic Gyroscope (FOG)is the key device in laser continuous dynamic pavement deflection measurement vehicle, that is used to measure the in stantaneous angle between a rigid staff and the horizontal direction. The precision of deflection measurement srely directly on the key FOG parameters, Such as the scale factor, output delay, And bias. The traditional calibration methods for these parameters require cumbersome mechanical rotating platforms. To address this problem,this paper introduces an ovel method to calibrate the key parameters of FOG. A new calibration device was designed with two high precision laser vibrometers fixed on each end of a rigid staff, and an under testing FOG was mounted in the middle. According to the locomotion equation, We established a mathematical model to describe parameters, and then solved by a least mean square calculation. The novel method proposed in this paper utilizes a simple mechanical platform, a concise experiment process and easy to solve parameters. Experiments verified that the measurement results from the proposed method are precise. This method was successfully applied in the first continuous dynamic pavement laser deflection measurement vehicle in China.