Abstract: Investigates the fluid driven gyro used in attitude stabiliztion systems. Working principle of the fluid driven gyro used in attitude stabilization system is introduced, and the mathematical model derived by building the gyro torque equations. Output signals of the gyro are tested by the method of velocity sudden stopping, and the simplified system transfer function of the gyro is built up, based on the experimental curves. Output signals of the gyro contain both the angular information and the angular velocity information of the carrier, whose magnitudes lie on the time constant.