The sensitive bearing with the gyroscope frame is the key part ofthe navigation system, the magnitude and fluctuation of whose startingfriction moment and dynamic friction moment at lower speed are theimportant factors of direction and orientation system in the applicationof spaceflight, aviation,navigation, precision guidance materiel facility,and are decisive in the performance andsafety of the systems. To thebearing with the gyroscope frame, its increasing of friction moment andits fluctuation is the root cause of bearing invalidation. As far as the sensitive bearing with the gyroscope frame on thecondition of normal starting and lower speeding, due to thecomprehensive action of all kinds of impaction factors, whose value ofmoment will take on a random, unstable periodic variation. And processquality is the main factor of the fluctu ation of bearing friction moment.At present, the mathematical model of friction moment formula hasbeen founded and experience coefficient been obtained on the conditionof ideal process quality. Only on the basis of bearing main parameterfactor can the magnitude of friction moment be calculated, but themagnitude and fluctuation cant be theoretically calculated andanalyzed on the basis of minor parameter factor.For above-mentioned reasons, aiming at the radial ball bearing,the dissertation studies the mechanism of friction moment occurrenceon the basis of the researches of bearing kinematics, pseudostatic,tribology and elastohydrodynamics lubrication theory, by the way ofestablishing the mathematical model which is about the Impaction ofellipticity of interior and exteriorrace on the friction moment andmaking use of high precision Monte-Carlo method, numerically solvesthe established nonlinear equations, finally develops a correspondingsoftware about pseudostatics of friction moment with Visual C++. Therelation of the race ellipticity and bearing friction moment istheoretically analyzed. And the comparison experiment and analysis ismade through measuring dynamic moment under lower speed. Theexperimental validation show that the mathematical model establishedin the dissertation which is analyzing friction moment in view of theellipticity of interior and exterior race is feasible. The developeddynamic performance analytical software about pseudostatics is liable.At last, various impaction facto rssuchas ferrule circularity, radialplay, surface performance and quality of ferrule, separ ator structure etc.is experimented and analytically study. The result can provide certaintheoretical basis for sensitive bearing optimum design, processparameters and quality control.