The invention discloses a horizontal extruder plunger type cylinder and a plunger slide guiding system thereof. The plunger slide guiding system comprises a plunger gland mounted at the end part of the plunger type cylinder and a sealing element and an eccentric guide sleeve mounted in the plunger type cylinder, wherein a plunger is arranged in an inner cavity of the plunger type cylinder and moves in the central axis direction relative to the plunger type cylinder; the eccentric guide sleeve is arranged between the plunger type cylinder and the plunger; the central axis of the inner cavity of the eccentric guide sleeve, the central axis of the plunger and the central axis of the extruder plunger type cylinder coincide; the external diameter of the plunger is matched with the internal diameter of the eccentric guide sleeve; and the external diameter of the eccentric guide sleeve is matched with that of the plunger type cylinder. As the eccentric guide sleeve can eliminate the accumulated error, caused by the processing, manufacturing and mounting manner, between the plunger and the eccentric guide sleeve and between the eccentric guide sleeve and the extruder plunger type cylinder, the extruder plunger type cylinder and the plunger are concentrically arranged, and the gap between the eccentric guide sleeve and the sealing element can be compensated to form proper lubricating oil film thickness.