A backlight module, at least includes an outer frame, a bottom frame, an upper frame, a reflector and a light source. The upper frame and the bottom frame are mounted within the outer frame and are removably coupled to each other. The upper frame is disposed above the bottom frame and the bottom frame can be separated from the outer frame when the backlight module is inverted. The reflector is disposed under the upper frame and on the bottom frame and the reflector can be removed after the bottom frame is separated from the outer frame. The light source disposed under the upper frame and above the reflector and the light source can be changed after the reflector is removed. This backlight module enables users to directly exchange the light source by just simply taking out the bottom frame and the reflector sequentially. By this, the damage of the display panel, the multilayer optical film and the light guide plate caused by hitting and scratching during the exchanging process is prevented.