The invention relates to a component force type rotor of an underground cylindrical linear motor. The component force type rotor is applied to a plunger pump of an underground oil production linear motor in an oil field and is characterized in that annular grooves are processed on a central rod; a rotor magnetic yoke is sleeved on the outer wall of the central rod; an inner magnetic steel sleeve is embedded in each annular groove of the central rod; the inner magnetic steel sleeve is of a semi-circular body; two semi-circular bodies are opposite to form one inner magnetic steel sleeve; circular magnetic steel is sleeved on the outer wall of the inner magnetic steel sleeve; an outer circular magnetic steel sleeve is sleeved on the outer wall of the circular magnetic steel; limiting nuts are respectively fixed at two ends of the central rod; and rotor jackets are sleeved on the outer walls of the rotor magnetic yoke and the outer magnetic steel sleeve. The component force type rotor disclosed by the invention has the effects of acting an electromagnetic force stressed by each magnetic steel on the steps of the annular grooves of the central rod, preventing the electromagnetic force from acting on the bottom magnetic steel, and effectively preventing from generating magnetic force concentration at the lower part of the whole rotor. Because the inner magnetic steel sleeve is divided into two parts, the component force type rotor can be conveniently installed in the annular grooves on the central rod.