2D DCT plays an important role in image procession and video encoding. Based on all I-frame video encoding of MPEG-2, 2D DCT is implemented on FPGA. 8×8 2D DCT is changed into eight 1D DCT combination with some butter-fly operations and reordering operation. It is provided in simulation that the implementation of 2D DCT can run at 74.25 samples per second with only one 1D DCT module.