The invention discloses a backplane, a back light module, and an LCD device. The backplane comprises a backplane surface and side walls arranged on the sides of the backplane surface. The backplane further comprises at least one layer of stacked plate fixed to the side walls in a stacked mode. Because the side walls of the backplane of the invention are provided with at least one layer of stacked plate fixed to the side walls in stacked mode, the thickness of each side wall of the backplane is increased and thus reinforces the strength of each side wall, and the total strength of the backplane is reinforced under the support of the side walls and the stacked plates thereof. Besides, that the strength of the side walls is reinforced avoides the arrangement of stiffeners on the backplane surface, which reduces the total thickness of the backplane. Thus, on one hand, the total strength of the backplane is guaranteed, on the other hand, it is possible to reduce the thickness of the backplane and make a thinner LCD device.