The embodiment of the invention relates to a test method of deformation of a transformer winding, a test device of deformation of the transformer winding, and a storage medium so as to achieve the goals of conveniently and accurately determining whether the transformer winding deforms or not and determining the deformation degree when a transformer has the winding deformation. The test method comprises the following steps of determining the electric capacity of each winding after the grounding relative to other two windings; determining the corresponding electric capacity change rate of each winding on the basis of the electric capacity; and determining the deformation condition of a middle winding and an inside winding on the basis of the electric capacity change rate.