A rimless display device and a preparation method thereof, the rimless display device comprises a flexible substrate formed on a rigid base plate (1), the flexible substrate is provided with a display region (2) having an organic light-emitting layer arranged therein and a non-display region (3), wherein, after a part of the rigid base plate at a location corresponding to the non-display region (3) is removed, the non-display region (3) of the flexible substrate is fixed on a lateral surface or a rear surface of the display device after the non-display region (3) is folded. This rimless display device can achieve a real rimless display screen body, thereby further increasing the screen proportion and greatly improving the view effect.