The utility model discloses a device for screening the nonuniformity of a backlight and a test method of the device. The device comprises a liquid crystal screen (1), a structural member (2) and a diffusion board (3), wherein a screen framework for mounting the liquid crystal screen (1) and a board framework for mounting the diffusion board (3) are arranged on the structural member (2); the section of an inner cavity of the structural member (2) is rectangular, a backlight framework (6) is arranged in the inner cavity of the structural member (2), the backlight (5) is fixed on the backlight framework (6), one surface with the backlight (5) of the backlight framework (6) faces the diffusion board (3), and a circuit board (8) with a debugging line is arranged on the backlight (5); and the diffusion board (3) is arranged between the liquid crystal screen (1) and the backlight (5). Before the backlight is arranged into a liquid crystal display module, the uniformity of the backlight is screened by virtue of the device, so that the uniformity of the backlight arranged into the liquid crystal display module is guaranteed, and further, the uniformity of the liquid crystal display module is guaranteed.