The invention relates to an AC-DC (alternating current-direct current) switching power supply and a power triode structure thereof. The power triode comprises a substrate, at least two base regions, emitters, collector electrode pins, at least two base electrode pins and at least two emitter pins, wherein the substrate is used as a collector electrode, the at least two base regions which are isolated from each other are formed on the substrate; each base region is provided with an emitter and a collector electrode pin connected with the substrate, the at least two base electrode pins are connected with the base regions electrically, and the at least two emitter pins are connected with the emitters electrically, and the substrate, each base region, the emitter and the corresponding pin on each base region form a triode unit. The AC-DC switching power supply comprises a power supply management circuit and a switching pipe which is electrically connected with the power supply management circuit; and the switching pipe is provided with the power triode structure. According to the invention, under the premise of controlling cost, the performances of the switching power supply are ensured.