In order to improve the surface quality of servo valve core,an improved free abrasive finishing method was presented.The C616 machine tool was modified. A second spindle and an abrasive spraying device were added to the machine tool. The surface of the part was polished with a felt wheel and an abrasive slurry. The surface morphology of the part before and after machining was observed by a metallographic microscope.Experimental results show that within the given range, the 8 000# white corundum powder with a concentration of 10% and the speed of the felt wheel of 8 000 r/min are used for 5 min, the surface streaks remaining after the parts are turned off are obviously removed, which effectively improves the surface quality of the servo spool.