The invention belongs to the technical field of manufacturing of a copper flat wire for a power transformer winding and particularly relates to a copper flat wire softening control deformation deviceand a preparation process thereof. The device includes a guide wheel set, a shaping die and a traction wheel which are arranged in sequence, wherein an outer side of the guide wheel set is an incomingend, an outer side of the traction wheel is an outgoing end, the guide wheel set includes an upper guide wheel and a lower guide wheel, the upper guide wheel and the lower guide wheel are correspondingly arranged up and down, the lower guide wheel is located in a cooling water tank, an electromagnetic induction coil and a dryer are arranged between the upper guide wheel and the lower guide wheel,the electromagnetic induction coil is disposed in the incoming direction of the lower guide wheel, and the dryer is disposed in the outgoing direction of the lower guide wheel. The device is advantaged in that the structure is simple, the processing cycle of the entire manufacturing process of continuous softening control deformation of the copper flat wire is shortened, a method for softening ofa hard copper wire is improved, manufacturing cost is reduced, the current of an electromagnetic induction coil and the traction speed of the copper wire can be adjusted in the process, precise adjustment of a copper wire hardening index is achieved, and manufacturing efficiency is improved.