The paper introduces the testing system and analysis method for the dynamic axis center motion track of the bearing. The system consists of driving device of air spindle, measuring microdistance instrument by electric capacity in noncontact, signal analysis instrument and the computer hardware and software. Many kind signal evaluation methods are adopted. The testing accuracy is high. Actual error is ≤0.02 μm. The testing system can make measurement and analysis for axis center motion of precision miniature bearing and rotating spindle of military gyroscope and effectively show dynamic performance.