With consideration of centrifugal force and gyroscopic moments from rotating components with high speed, the Timoshenko beam element and disk element are used to model the spindle rotor, disk and the spindle housing. The Jones’ bearing model is extended and a nonlinear model for high-speed bearings is obtained. By assembling the model of each component, the nonlinear dynamic equation of the whole spindle system is given with experimental validation. The speed effects within the spindle-bearing sytem and their influences on the dynamic properties of the whole system are studied systematically from three aspects, i.e., gyroscopic moment of the rotor, centrifugal force of the rotor, and bearing softening. The results show that, when the damping ratio is relatively large(1%~5%), the gyroscopic moment can hardly affect the direct transfer function, but can change the cross transfer function obviously; with the rise of the spindle speed, the centrifugal effect of the spindle rotor decreases the stiffness of the spindle system gradually, which causes the drop of the natural frequencies of the high-speed spindle system; the centrifugal force’s effect of the spindle rotor and bearings’ softening effect need to be included synthetically so as to accurately simulate the dynamic properties of the high-speed spindle system.