The present invention relates to a volume pulsed deformation plasticating and conveying method and device by an eccentric rotor. The rotation of the eccentric rotor and the rolling of the rotor in the inner cavity of a stator during constant reverse revolutions cause the volume of the material between the eccentric rotor and the stator to periodically change alternatively along the axial direction and the radial direction of the stator, thereby enabling the volume pulsed deformation plasticating and conveying of the material. The volume pulsed deformation plasticating and conveying device consists of a stator, of which the inner cavity comprises multiple alternatingly disposed spiral segments and straight segments, and an eccentric rotor comprising multiple alternatingly disposed eccentric spiral segments and eccentric straight segments. The eccentric rotor is disposed in the inner cavity of the stator. The eccentric spiral segments and the eccentric straight segments of the eccentric rotor correspond one-to-one with the spiral segments and straight segments of the stator. The present invention can be used as the extruding system of an extruder or be combined with different plunger injection units to form a plasticating injection device of an injection molding machine. The present invention has a short thermo-mechanical distance for the materials, low energy consumption, and wide adaptability.