The invention discloses an ultrathin switching power supply for OLED televisions. The ultrathin switching power supply comprises a power supply shell, a PCB and a heat dissipation unit. The power supply shell comprises a metal base and a cover. The PCB is mounted on the metal base. Ventilating dustproof nets are detachably installed on the two side walls of the cover. The heat dissipation unit comprises a suction fan, an exhaust fan and a heat dissipation pipe set. The heat dissipation pipe set comprises two hard air pipes. The adjacent ends of the two hard air pipes are hinged to each other.One end of one hard air pipe is hinged to the inner wall of the cover, and a slide block is hinged to one end of the other hard air pipe. An electromagnet is mounted at the hinge part of the two hardair pipes on the inner wall of the cover. Iron sheets matched with the electromagnet are installed on the hard air pipes. A compression spring is fixed to the middle of the hard air pipe, hinged to the inner wall of the cover, in the two hard air pipes. According to the heat dissipation device, the heat dissipation unit is arranged, and the direction of air sprayed out of a nozzle is continuouslychanged, so that the heat dissipation area is enlarged, the heat dissipation angle is changed, and the heat dissipation efficiency is improved.