The invention discloses a two-dimension inverse transformation method in an audio video coding standard and a realization circuit thereof, pertaining to the technical field of digital audio and video.The inverse transformation method of the invention includes that input data is divided into four groups and a first clock cycle multiplies a column vector of the j group by the column vectors in therows of 0 and 3 of an inverse transformation coefficient matrix and the intermediate result is computed by a butterfly computation to obtain the final results, namely X0j and X3j; a second clock cyclemultiplies the column vector of the j group by the column vectors in the rows of 1 and 2 of the inverse transformation coefficient matrix and the intermediate result is computed by the butterfly computation to obtain the final results, namely X1j and X2j, wherein, j is equal to 0, 1, 2 and 3. The realization circuit of the invention comprises four in-group computation modules used for computing the column vector of input data and two inter-group computation modules used for computing the output of the in-group computation modules. The inverse transformation method and the realization circuitof the invention have high computing speed and low costs without an extra memory cell to store the intermediate results generated in the integer DCT inverse transformation or the Hadamard inverse transformation.