A backlight module includes a housing, at least a light-mixing tube, a plurality of light emitting devices, and at least a reflector. The housing includes a bottom sheet and a frame, in which the bottom sheet and the frame define a chamber. The frame is a hollow structure, and inner walls of the frame define the light-mixing tube. The light emitting devices are disposed at a light entrance of the light-mixing tube. Lights generated by the light emitting devices enter the light-mixing tube from the light entrance, mix in the light-mixing tube, and emit from a light exit of the light-mixing tube. Lights emit from the light-mixing tube are reflected at the reflector and therefore are reflected into the chamber.