In this paper，first，We introduce a methed for computation of two-dimensional DFT by inverse Polynomial Transforms (When k₂ is odd or oven，We discuss respectively). Then We develop mixed algorithm to compute two-dimensional DFT，the arithmetic operand of this technique for the N×N(N=2^t) two-dimensional DFT is Mu=?N²log₂N—?N²+N Ad=2N²log₂N. As Compared with the conventional radix-2 two-dimensional FFT,this mixed algorithm requires less number of multiplications (decrease by 20-40%) and same number of additions.