The invention discloses a method for simultaneously detecting precise ball hinge ball-head eccentricity and ball arm space attitude. At present, the method for effectively measuring ball hinge ball-head eccentricity and ball arm space attitude is few. The method comprises the following steps: acquiring distance between an emitting point of an ultrasonic emitter and a receiving point of each of four ultrasonic receivers, decoupling an included angle between a bar arm central axis and an Z axle and the included angle between a projection line of the bar arm central axis on an XOY plane and a X axle through a geometric principle; detecting capacitance CG1 of a spherical-crown electrode G1 and the capacitance CG3 of the spherical-crown electrode G3 to obtain the differential capacitance therebetween; detecting capacitance CG2 of a spherical-crown electrode G2 and the capacitance CG4 of the spherical-crown electrode G4 to obtain the differential capacitance therebetween; detecting the capacitance CD1 of the spherical-crown electrode D1 and the capacitance C2 of the spherical-crown electrode D2 to obtain the differential capacitance therebetween; and obtaining X, Y and Z values of the ball eccentricity. The ball arm space attitude of the ball hinge is acquired in real time based on the ultrasonic ranging principle, and the eccentricity of ball head of the ball hinge ball-head can beaccurately acquired based on the spherical capacitance principle.