The error generated by the test equipment is an important source of the error of the high-precision fiber optic gyroscope, which limits the further improvement of the accuracy of the fiber optic gyroscope. This paper analyzes the error of the fiber optic gyroscope based on the test equipment such as turntable, tooling, time reference source, etc., and studies its influence on the error of the high-precision fiber optic gyroscope through simulation analysis and experiment, and proposes improvement and suppression methods. After improvement, the zero offset error generated by the tooling has been reduced by two-thirds, the absolute error of the scale factor generated by the turntable and the repeatability error of the scale factor generated by the time reference have been reduced by an order of magnitude, improving the accuracy of high-precision fiber optic gyroscopes. As well as testing improvements provides guidance.