The invention provides an automatic centering ball sealing mechanism restraining fluid exciting force. The automatic centering ball sealing mechanism restraining fluid exciting force comprises an outer shell with the inner surface provided with a spherical raceway, a sealing block with the outer surface provided with at least one raceway and a rotor in sealing connection with the sealing block. At least one row of balls are further arranged between each raceway of the sealing block and the spherical raceway of the outer shell. Each raceway corresponds to one row of balls. Each ball makes point contact with the spherical raceway of the outer shell. Each ball makes arc face contact with the corresponding raceway of the sealing block. The sealing block surrounds and is sealed to the outer surface of the rotor and deflects along with the rotor. The automatic centering ball sealing mechanism has the beneficial effects that by means of the automatic centering ball sealing mechanism restraining fluid exciting force, the fluid exciting force caused by rotor inclination or deflection deformation can be reduced, and accordingly the fluid exciting resisting capability of the automatic centering ball sealing mechanism can be improved.