A curvature adjustment device of a curved display screen, a curvature adjustment method for a curved display screen and a curved display device. A curvature adjustment device for a curved surface display screen includes: a supporting back plate, which is a supporting plate having a fixed curvature; an elastic back plate, which is connected to the supporting back plate and capable of being elastically deformed to change a curvature; and an adjusting device, configured to adjust the curvature of the elastic back plate. The adjustment device is used to change the curvature of the elastic back plate, such that the display screen can be curved into different arc shapes, improving the applicability of the curvature adjustment device of the curved display screen.