Abstract: The triple resonance pulse transformer is a new type of pulse transformer, which is based on air-cored transformer. The voltage across the pulse transformer is significantly less than the output voltage; instead, the full output voltage appears across the tuning inductor. By analyzing the pulse transformers lossless circuit, the analytical expression for the output voltage and the relation of the triple resonance circuit parameters are presented for the eigen frequency ratio of the circuit being 1∶2∶3, and the maximal ratio of peak load voltage to peak transformer voltage is 2.77. Then a design method for the triple resonance pulse transformer, iterative simulation method, is presented. A pulse power generator based on the triple resonance pulse transformer developed from an air-cored transformer is developed accordingly. The experimental results indicate that the ratio of the peak output voltage to the peak voltage on high voltage winding is 2 and the peak output voltage of the triple resonance pulse transformer is 600 kV. The theoretical and experimental results agree well with each other. Therefore, any double resonance pulse transformer may be developed into a triple resonance pulse transformer.