The invention discloses a transformer winding deformation assessment method, which comprises the following steps: (1)acquiring temperature information of the environment a transformer winding laid and calculating the transfer function amplitude series X (k), and N is the length of the transfer function amplitude series of the transformer winding; (2)calculating a regular transfer function amplitude series Y (K); (3) calculating normalized covariance coefficient LRxy between the transfer function amplitude series of the transformer winding and the transfer function amplitude series of a regular transformer winding; (4)calculating the correlation coefficient of the transformer winding in each frequency band; (5) calculating conversion value of the correlation coefficient of the transformer winding in each frequency band in standard temperature; (6)assessing deformation degree of the transformer winding according to the correlation coefficient. The method can assess the deformation of transformer winding accurately.