A backlight module and a manufacturing method thereof are disclosed. The backlight module includes a frame, a thin-film thermoelectric device set, a first heat conductive layer, a light emitting diode (LED) light, a bulk thermoelectric device set, and a second heat conductive layer. The manufacturing method for backlight module includes a device preparing step, a thin-film thermoelectric device set mounting step, a first heat conductive layer preparing step, an LED light mounting step, a bulk thermoelectric device set mounting step, and a bulk thermoelectric device set mounting step. The technical effect of the invention is to realize the heat dissipation and the recovery and utilization function of the waste heat.