Disclosed are a method for preparing a curved surface backlight module, a curved surface backlight module and a display device. The method includes described below. An initial back panel is provided, where the initial back panel includes a first surface and a second surface which are opposite to each other, the first surface includes multiple first flat regions and multiple first convex curved regions, each of the multiple first convex curved regions is located between adjacent first flat regions, the second surface includes multiple second flat regions and multiple first concave curved regions. An initial lamp panel is provided. The initial back panel and the initial lamp panel are curved to form the curved surface backlight module, where a curving axis of the curved surface backlight module is parallel to curving axes of the multiple first convex curved regions and curving axes of the multiple first concave curved regions.