A backlight module is provided. The backlight module comprises a light source, a reflection panel, a back bezel, and an upper filtering apparatus. The reflection panel has a first upper portion, which is essentially disposed at an outer side of the light source, and is used to reflect lights projecting from the light source. The back bezel has a second upper portion which is essentially disposed at an outer side of the reflection panel. At least one of the first upper portion and the second upper portion forms an upper opening. The filtering apparatus covers the openings. The filtering apparatus is capable of changing the distribution of the temperature of the light source to allow more efficient lamp activity. As a result, luminance is increased and lamp life extended.