The invention provides an automatic tray stacking mechanical arm and controller, comprising a right base, a left base and a controller, wherein a right electric extension rod is connected above the right base, and is connected with a right joint 1, a right connecting rod 1, a right joint 2, a right connecting rod 2, a right fixed base and a right clamping hand; a left electric extension rod is connected with a left joint 1, a left connecting rod 1, a left joint 2, a left connecting rod 2, a left fixed base and a left clamping hand; the right electric extension rod is connected with the controller through a right connecting wire; the left electric extension rod is connected with the controller through a left connecting wire; an indicator light is mounted on the outer surface of the controller; and a single-chip, a storer, a relay and a battery set are arranged in the controller. Compared with the prior art, the automatic tray stacking mechanical arm and controller have the following beneficial effects: the purpose of automatic tray stacking can be realized; and after each operation, the indicator light can blink to prompt workers, so that the working efficiency is high, special workers are not needed to operate, and the operation is simpler.