With the development of power electronic technology and the distributed generations, it is expected that transformer function can be realized by using power devices and the bulk and cost of transformer will be reduced. So the DC-DC transformers whose voltage isn't regulated with the load and the input voltage are focused on in resent years. In this paper, a novel DC-DC transformer based on ZVS (zero volt switching) dual switch push-pull converters will be analyzed in detail. The output characteristics and ZVS conditions will be particularly discussed. The experiment results verify the performance of the proposed DC-DC transformer.