The invention discloses an automatic stacking device for thrust plates. The automatic stacking device comprises a rotating sucker mechanism, a shifting mechanism and a collecting mechanism. The rotating sucker mechanism comprises a base. A driving motor is installed at the edge of the base. The output end of the driving motor is provided with a driving gear. The driving gear is in linkage with a revolving support through a meshing structure. The top of a lower supporting column is provided with an upper supporting column and a revolving sucker. The revolving sucker is used for transmitting thethrust plates to a working position of the shifting mechanism under driving of the driving motor. The shifting mechanism comprises a bracket. An electric pushing rod is installed on the bracket. Theelectric pushing rod is connected with a shifting head and can drive the shifting head to shift the thrust plates into the collecting mechanism. The collecting mechanism comprises a stepper motor. Theoutput end of the stepper motor is connected with a ball screw shaft through a coupling. A tray used for stacking the thrust plates is installed in a collecting groove, and can move up and down alonga sliding groove under driving of the stepper motor.