Abstract: A triple resonance pulse transformer is developed based on a taper dual-winding magnetic core transformer, it has the advantages of is compact structure, small size and so on. The magnetic core of the transformer is made of 0.08 mm thick silicon steel strip with semilunar structure, and fastened in an aluminum cylinder. The primary and secondary windings consist of double parallel coils. Two taper high voltage windings are symmetrically wound in the groove of the organic glass skeleton and two output ends are welded together and drawn from axis of the cylinder. This structure may improve electric field distribution of the high voltage winding and achieve a coaxial output. The triple resonance circuit is composed of the core transformer, LC tuning circuit and a pulse forming line (27 pF). The tuning capacitor is the structure capacitance of a short coaxial transmission line, and the tuning inductor is wound in the non-uniform grooves of the organic glass skeleton with 0.08 mm diameter enameled wire. The experimental results indicate that the peak output voltage of the triple resonance pulse transformer is about 800 kV and the charging time is about 650 ns.It is demonstrated that a triple resonance pulse transformer can be developed based on a magnetic core pulse transformer.