The leakage magnetic field will increase sharply, causing the windings to bear excessive electromagnetic force when a short circuit accident occurs. Excessive short-circuit electromagnetism may lead to twisting and deformation of windings, which can even damage the transformer in severe cases. In order to study the short circuit electromagnetic force, a numerical calculation model of the transformer was developed based on actual transformer dimensions. Taking into account the actual winding structure, it is modeled using a pancake structure. Use two-dimensional axial symmetry model and ignore the impact of structural parts on magnetic flux density. The commercial simulation software COMSOL was applied to calculate the magnetic induction intensity and electromagnetic force. The current of the transformer, magnetic induction intensity and electromagnetic force of windings were obtained with commercial simulation software COMSOL. The simulation calculation shows that the magnetic induction intensity distribution is mainly concentrated between the outermost two windings. The axial electromagnetic forces of coils near the ends are larger. The radial electromagnetic force endured by each coil does not change much.