The principle of static angle measurement based on mechanically dithered ring laser gyro was described. The expression of angle measurement random error with gyro′s angle random walk coefficient and measurement time was analyzed and verified by checking the indexing errors of turntable. The systematic error of static angle measurement and the indexing errors of turntable were separated by using the permutation intercomparison method. Test results and analysis show that the static angle measurement method is robust under practical environment, the standard deviation of random error is less than 0.26″ and the systematic error is less than 1″. The key techniques for further improvement in accuracy were analyzed.