With the widespread application of various power converters in the field of power electronics, high-frequency transformers, as their key components, have an increasingly significant impact on the overall circuit performance due to their distributed parameters. This article aims to deeply analyze the distributed parameter characteristics of high-frequency transformers, based on dual active bridge (DAB) converters, and reveal their impact mechanism on circuit performance. Taking the widely used DAB converter as an example, the influence of distributed parameters of high-frequency transformers on their circuit characteristics is studied. The operating mode of single-phase modulation in the circuit is analyzed in detail, and a three capacitor equivalent model considering the distributed parameters of high-frequency transformers is constructed. The influence of distributed parameters of high-frequency transformers on circuit transmission performance was systematically studied using the Matlab/Simulink simulation platform. Subsequently, a high-frequency transformer prototype with a power of 15 kW/500 V/50 kHz was designed using the AP method. Ansys Maxwell finite element simulation software was used to calculate the distributed capacitance and leakage inductance values of the transformer, and DAB converter models based on equivalent circuits and finite elements were established to analyze the operational performance of the designed prototype and verify whether it meets the design requirements.