A backlight module includes a light-guiding plate, a back-light source disposed at a side of the light-guiding plate, and a frame structure disposed surrounding the light-guiding plate. The frame structure includes a border component, at least one first convex, and at least one second convex. The border component includes at least one first border and at least one second border. The first border and the second border are adjacent to each other and distributed along a first direction and a second direction respectively. The first convex protrudes from the inner surface of the first border and extends inward along the second direction. The second convex protrudes from the inner surface of the second border and extends inward along the first direction. The first direction is vertical to the second direction, and the top of the vertical height of the first convex is lower than that of the second convex.