The present invention provides a method and an apparatus for preparing a window having a predetermined shape, the method comprising the steps of: molding a window material into a predetermined window shape by means of a molding apparatus; and loading the window material onto the molding apparatus by means of a loading apparatus, wherein further comprised are the step of first aligning the window material, before loading same onto the molding apparatus, by means of a first alignment apparatus for X-axis alignment and Y-axis alignment and the step of second aligning the window material, after loading same onto the molding apparatus, by means of a second alignment apparatus for reference surface alignment. Therefore, by loading the window material onto the molding apparatus by means of the loading apparatus, time of loading the window material onto the molding apparatus can be drastically shortened and the cause of defects during the loading of the window material onto the molding apparatus can be removed, or, by quickly and accurately unloading from the molding apparatus the window material that has been molded by means of the molding apparatus, time of unloading the window material that has been molded by means of the molding apparatus can be drastically shortened and defects which may occur during the unloading of the window material that has been molded by means of the molding apparatus can be prevented, thereby enabling the preparation of a high quality window.