The invention discloses a totally-enclosed high-
voltage resistant magnetomotive multi-ball 
injector which comprises a shell, a union plug, a stepping motor, a strong magnetic driving rotor, a lead screw, a driven rotor, a ball selecting rod and two ball barrels, wherein the lower end of the shell is arranged on a fracture 
wellhead through a lower joint; two protruded limiting keys are symmetrically arranged on the wall of an inner cavity of the shell; the outer wall of the ball selecting rod is respectively and vertically provided with two through long grooves through which the corresponding limiting keys are inserted; openings in the upper ends of the two ball barrels are respectively sealed by a ball 
barrel end cover, and openings in the lower ends of the two ball barrels are respectively plugged by the ball selecting rod. The totally-enclosed high-
voltage resistant magnetomotive multi-ball injection is high in 
voltage resistant level, strong in sealing reliability, capable of realizing loading ball injection under voltage without stopping a pump in the working process, large in online ball injection quantity, simple to operate, high in ball injection reliability, capable of improving the ball injection precision, small in size, convenient to carry and 
mount, capable of realizing 
remote control, away from a 
high voltage area and safe to operate.