The invention relates to a simple overturning device and method for a box-shaped component. The overturning device comprises an overturning beam, a baffle and an enclasping cable. The overturning beamis composed of two steel plate strips which are arranged in parallel. One end of each steel plate strip is provided with multiple bolt holes, and the baffle is welded to the other ends of the steel plate strips. The baffle is composed of a flat steel plate and two reinforcing plates. The flat steel plate is arranged to be perpendicular to the reinforcing plates. The two ends of the enclasping cable are arranged to be in the ringlike form through steel wire rope end ties. The simple overturning device is simple in structure, small in weight and convenient to use and does not need multiple persons for operation; meanwhile, the overturning device is convenient and fast to operate; and safety and reliability are achieved in the overturning process, and a parent metal is not damaged.