As one of the key parts in electrostatic precipitator(ESP), the distribution parameters of high-power high-frequency high-voltage transformer not only directly affect the system performance, but also are the key parts of LCC series-parallel resonant circuit’s design.Based on energy method, this paper proposes a new method using transformer’s size data for the calculation of leakage inductance, then builds a transformer’s 3D model and uses finite element analysis(FEA) software ANSYS to simulate and verify the magnetic field distribution curve of the windings. Finally, compared with the actual test data of a 72kV/85kW high-power high-frequency high-voltage transformer for ESP, proves the effectiveness of the method and gives actual production certain guidance.