The invention discloses an optimal gyroscope combination selection method based on residual error generators. The method comprises steps as follows: (1), four gyroscopic instruments of four standby gyroscopic assemblies including three upright gyroscopic assemblies and one oblique gyroscopic assembly are divided into four groups of gyroscope combinations; (2), the three-axis angular speed of each satellite is calculated according to measurement values of the four groups of gyroscopic combinations according to mounting matrixes of the standby gyroscopic assemblies, and three-axis angular speeds of the four satellites are obtained; (3), the three-axis attitude provided by a star sensor and the three-axis angular speeds, calculated by the four groups of gyroscopic combinations, of the satellites are used for forming the residual error generators, and four attitude residual errors are obtained totally; (4), an evaluation function of each attitude residual error is solved, the four evaluation functions are sequenced according to numerical magnitudes, and the smallest group is the optimal gyroscope combination. The gyroscope combination with the optimal performance is dynamically selected in orbit in real time, redundancy of the gyroscopic assemblies on the satellite is effectively used, angular speed information with higher accuracy can be provided for an attitude control system, and the method has certain fault-tolerant capacity for gyroscopic faults.