A digital drive closed-loop method with gain compensation was proposed to improve the stability of scale factor for a micro-machined gyroscope. The working principle of the micro-machined gyroscope was analyzed and the analysis results on the dynamic equation show that in order to improve the stability of the scale factor, the stability of drive-mode vibration speed of the gyroscope should be improved. However, the stability of drive-mode vibration speed of the gyroscope is dependent on the stability of gain of a C/V conversion circuit in the drive closed-loop. Therefore, a gain compensation algorithm was proposed and the digital drive closed-loop with gain compensation was designed by combining with a automatic gain control loop and a phase locked loop. Simulation results show when the gain of C/V conversion circuit changes 7.4% in relative, the amplitude of vibration velocity changes from 7.29% without gain compensation to 0.12% with gain compensation. Experiment results indicate that the temperature coefficient of scale factor within -40℃ to 60℃ is reduced by 90% after gain compensation. It verifies that the digital drive closed-loop with gain compensation can significantly improve the stability of scale factor for the micro-machined gyroscope.