The invention relates to a drive circuit of an electronic transformer, which comprises a trigger circuit, a switching circuit and an output transformer T2, wherein the trigger circuit provides a trigger signal for the switching circuit, the switching circuit provides a high-frequency output signal for the output transformer; the output transformer T2 comprises a primary winding T2-5, a secondary load winding T2-6 and a secondary drive winding; and the switching circuit comprises an LC oscillation circuit consisting of an oscillation capacitor and the secondary drive winding, and the LC oscillation circuit controls the on or off of triodes of the switching circuit in sequence. Therefore, even if the output end of the output transformer T2 is in a no-load close to zero or light-load state, the primary winding T2-5 has a certain voltage value, and the secondary drive winding can induce a corresponding voltage value so as to realize drive process. Because of the advantages, the invention can be applied to the electronic transformer with a heavy power load and a load close to a zero output power.