A removable electric controller for a garage door opener includes a base unit, a cover and a control box unit. A box lid of the control box unit is slidably connected to a connecting surface of the cover. A guide insertion end of a control circuit board of the control box unit is connected to a main connecting port module of a circuit terminal connecting plate on the base unit. The cover and the control box unit are detachable. A driving member, a light source member, an inductive circuit line and a power member of the base unit are connected to wiring port modules of the circuit terminal connecting plate, so that the wiring is in the way of modulization. The control circuit board of the control box unit can be replaced with ease, providing a convenient and simply assembly.