The invention relates to a transformer state evaluation method and apparatus. The method comprises the following steps: converting real-time operation parameters of a transformer into a relative deterioration degree; substituting the relative deterioration degree into a membership function, and obtaining a first evaluation matrix; obtaining a first constant weighting coefficient matrix from fault data of the transformer; obtaining a first connection degree coefficient matrix by use of the membership function; obtaining a matrix by multiplying the first evaluation matrix by the first connection degree coefficient matrix, and forming an evaluation value matrix through elements in the j-th row and in the j-th column in the matrix; obtaining a variable weighting coefficient matrix by use of the evaluation value matrix and the first constant weighting coefficient matrix; obtaining a second evaluation matrix by use of the first evaluation matrix and the variable weighting coefficient matrix; obtaining a second connection degree coefficient matrix by use of the first connection degree coefficient matrix and the variable weighting coefficient matrix; and obtaining a matrix by multiplying the second evaluation matrix by the second connection degree coefficient matrix, and forming a connection degree matrix through elements in the i-th row and in the i-th column in the matrix; and evaluating the state of the transformer by use of the connection degree matrix.