The invention provides a dynamical simulator for an abnormal structure change fault of a transformer. A transformer body, an iron core arranged in the transformer body and windings wound around a column of the iron core are included, the top of the transformer body is provided with three groups of high-voltage bushings, the three groups of high-voltage bushings are connected with the windings in the transformer body respectively, the iron core includes an upper part of silicon steel plates and a lower part of silicon steel plates, the lower part of an E-shaped structure is used to accommodate three-phase windings, the upper part is of a linear structure, a yoke on the iron core is formed by laminating the silicon steel plates, the two ends of the yoke are provided with upper clamping pieces, the yoke on the iron core and the upper clamping pieces are fastened to form an integral structure via an axial pull bar of the upper clamping pieces, each winding is of a three-segment structure, and every two segments are connected via a cold pressing joint. The dynamical simulator can simulate different fault degrees accurately, and integrate different diagnosis results to provide comprehensive data and theory support for a decision maker and further to provide basis for diagnosis on the abnormal structure change fault of the transformer.