In view of the defects in the dynamic and static pressure spindle system of 3MK133 channel grinder, the shallow groove of the throttle is easy to block and inconvenient to disassemble and clean, and the end-mounted flow restrictor is proposed to replace the original built-in shallow groove restrictor, change the gap throttle to capillary throttling, and adjust the taper, oil return path, sealing device and sealing method of the tapered bearing in the spindle system accordingly. The finite element calculation and analysis show that the improved bearing has the typical characteristics of pressure distribution of dynamic and static pressure bearings, which effectively improves the bearing capacity, reduces the friction power consumption, has a good throttling effect, and maintains the various excellent properties of the original spindle system.