The invention relates to an inertial space gyro calibration test method based on a three-shaft turntable; while a gyro assembly attitude rotation is provided by the three-shaft turntable, the compensation dosage of the earth autorotation angular velocity is calculated according to the real-time rotating angle output of three rotating shafts of the three-shaft turntable, so that the influence of earth autorotation on the gyro measurement output is eliminated, and the inertial space constant angular velocity required for a gyro calibration algorithm is ensured. At the same time, based on attached rotation characteristics of the three rotation shafts of the three-shaft turntable, the method defines a rotation sequence rule of the three rotation shafts and a three-shaft turntable body coordinate system and a reference inertial coordinate system having the initial zero coinciding with the ground horizontal coordinate system, and provides a reference benchmark for determining the inertial system angle increment according to the gyro output and for determining the inertial system attitude according to the rotation angle output of the three rotation shafts of the three-shaft turntable. The method can significantly improve the precision of a ground gyro calibration test, can guarantee the ground to perform effective calibration and test result calibration on a gyro assembly, can establish a good foundation for performing relevant calibration tests of satellites in orbit, and improves the determination precision of the gyro attitude.