A backlight module, comprising: a light guide plate having a light emitting side and a rear side opposite to the light emitting side, and a plurality of lateral sides (S3, S3', S3", S4) each of which connecting the light emitting side and the rear side, at least a first side of the plurality of lateral sides (S3, S3', S3", S4) is a light incident side configured to receive light from a light source, and at least a second side (S3, S3', S3") of the plurality of lateral sides (S3, S3', S3", S4) is not the light incident side; a light barrier attached to the second side (S3, S3', S3") and in contact with the second side (S3, S3', S3") for blocking light propagation, the light barrier fixedly positioned relative to the light guide plate; and a mold frame on a periphery of the light guide plate, the mold frame comprising at least one spacer; wherein the light barrier comprises at least one protruding support protruding away from an outer surface (S5, S5', S5") of the light barrier, the outer surface (S5, S5', S5") being on a side of the light barrier distal to the second side (S3, S3', S3"); and each of the at least one protruding support having a third side and a fourth side opposite to the third side, the third side being on a side of the fourth side proximal to the light emitting side; each of the at least one spacer is configured to be disposed on and supported by a third side of a corresponding each of the at least one protruding support,a normal distance between the third side and the rear side is less than a thickness of the light guide plate; wherein the at least one spacer is configured to be positioned between the corresponding at least one protruding support and a liquid crystal display panel to be assembled with the backlight unit, such that the relative position of the liquid crystal display panel and the light guide plate is confined. a light guide plate having a light emitting side and a rear side opposite to the light emitting side, and a plurality of lateral sides (S3, S3', S3", S4) each of which connecting the light emitting side and the rear side, at least a first side of the plurality of lateral sides (S3, S3', S3", S4) is a light incident side configured to receive light from a light source, and at least a second side (S3, S3', S3") of the plurality of lateral sides (S3, S3', S3", S4) is not the light incident side; a light barrier attached to the second side (S3, S3', S3") and in contact with the second side (S3, S3', S3") for blocking light propagation, the light barrier fixedly positioned relative to the light guide plate; and a mold frame on a periphery of the light guide plate, the mold frame comprising at least one spacer; wherein the light barrier comprises at least one protruding support protruding away from an outer surface (S5, S5', S5") of the light barrier, the outer surface (S5, S5', S5") being on a side of the light barrier distal to the second side (S3, S3', S3"); and each of the at least one protruding support having a third side and a fourth side opposite to the third side, the third side being on a side of the fourth side proximal to the light emitting side; each of the at least one spacer is configured to be disposed on and supported by a third side of a corresponding each of the at least one protruding support,a normal distance between the third side and the rear side is less than a thickness of the light guide plate; wherein the at least one spacer is configured to be positioned between the corresponding at least one protruding support and a liquid crystal display panel to be assembled with the backlight unit, such that the relative position of the liquid crystal display panel and the light guide plate is confined.