Abstract: The normal operation of power transformer is related to the safety and stability of the whole system. Under the long-term operation condition, winding deformation is a common type of transformer faults. This paper mainly tests the winding deformation of # 2 main transformer of 110kV Fenghuang substation in Zhaotong Power Supply Bureau,.It analyzes the experimental data of short-circuit impedance method, frequency response method and shock wave method, tests the deformation of transformer winding, and proves the shock wave method is considerable reliable in the transformer winding deformation test.