Abstract: The leakage magnetic field of converter transformers can cause the loss and local overheating of structural components（clamps, oil tank）, this paper proposes a method for the rapid calculation of the leakage magnetic field and loss of clamps and oil tank in converter transformers using mirror imaging. The mathematical model and calculation principles of the leakage magnetic field and loss for clamps and oil tank are presented. The finite element calculation are carried out, and the calculation and analysis of the leakage magnetic field of the converter transformer and the loss at its clamps and oil tank are conducted under the three-dimensional eddy current field, and the analytical method is compared with the finite element method. Finally, experiments on no-load current, magnetic density and load loss of the converter transformer are carried out to verify the correctness of FE method and indirectly verify the feasibility of the proposed scheme.