The invention discloses a press fitting device for a rubber sleeve bearing of a screen box rocker of a harvester. The device comprises a positioning base (2) which is fixedly arranged on a press working table to fix the screen box rocker (3), wherein an assembly end of the screen box rocker (3) is upwardly perpendicular to the working table; the positioning base (2) is provided with a guide seat (4) which covers the assembly end of the screen box rocker (3); the rubber sleeve bearing (6) is arranged in the guide seat (4) and is downwardly arranged on the assembly end of the screen box rocker (3) through press fitting by a pressing head (7) just above the rubber sleeve bearing (6); the guide seat (4) is provided with a floating positioning device (5), which can float to contract, for clamping and positioning the rubber sleeve bearing (6). The press fitting device is used for press-fitting the rubber sleeve bearing of the screen box rocker, is easy to operate, has high production efficiency, is low in labor intensity, guarantees the consistency of the press fitting, eliminates the hidden trouble of quality of a product and is suitable for large-scale assembly production.