Abstract: With the gradual maturity of the laser gyro manufacturing process and the breakthrough of lock-in and other major issues, the laser gyro goniometer has become a high-precision and high-sensitivity multi-parameter goniometer. This paper carries out a comprehensive test for its metrological performance for the first time and analyzes the main error sources of the laser gyro goniometer in detail, including three main error sources such as the installation error of the laser gyro, the turntable unlevel error, and the unstable error of the rotating speed. The simulation and estimation of the error introduced by each factor are analyzed. The random error of the laser gyro goniometer is also analyzed by using the classical Allan variance method. The results show that the uncertainty of comprehensive angle measurement is 0.4 ", and the angle measurement error is better than ± 0.5″.